NanoPlasMeta 2026 Abstracts

Area 1 - Nanophotonics, Plasmonics and Metamaterials

Area 1 - Nanophotonics, Plasmonics and Metamaterials

Nr: 35
Title:

Optically Enhancing or Detecting Single Molecules on DNA Origamis (Invited)
Authors:

Sebastien Bidault
Abstract: The ability to monitor single molecules or biomolecules with light is at the heart of numerous technologies ranging from diagnostic tools in biotechnology to single-photon sources in quantum technologies. However, single molecules interact extremely weakly with optical electromagnetic fields at room temperature: a fluorescent molecule resonantly interacts with less than one in a million photons that are focused on it, while, for a typical biomolecule, this value drops by a further 6 orders of magnitude. Using DNA origamis in conjunction with gold nanoparticles, we craft complex hybrid nanostructures that are capable of translating the detection of single short DNA strands into macroscopic color changes or of enhancing the fluorescence of single molecules by several orders of magnitude. These architectures open exciting perspectives for the development of new biosensing strategies with single molecule sensitivity, as well as for the study of coherent interactions between light and single quantum emitters at room temperature.
Nr: 36
Title:

Color Routing and Beam Steering of Single-Molecule Emission with a Spherical Silicon Nanoantenna (Invited)
Authors:

Maria Sanz-Paz, Nicole Siegel, Guillermo Serrera, Javier González-Colsa, Fangjia Zhu, Karol Kolataj, Minoru Fujii, Hiroshi Sugimoto, Pablo Albella and Guillermo Pedro Acuna
Abstract: Nanoscale photon sources such as fluorescent molecules exhibit a dipole-like emission pattern, significantly limiting the amount of light that can be collected and hampering their incorporation into flat on-chip optical components. Therefore, developing directional optical emitters with tunable angular responses in the visible range is crucial for applications ranging from designing efficient integrated optical systems to high-sensitivity screening of molecular species. While optical antennas have been introduced to control the radiation pattern of nanoemitters, the overall sizes of the reported systems are typically larger than the wavelength of the radiation, and the designs often involve high-loss plasmonic nanoparticles. Individual high-refractive-index dielectric nanoparticles (HRID NPs) can overcome these limitations as they can generate electric and magnetic dipole responses, whose interference can strongly affect their scattering pattern. It has been theoretically shown that a single HRID NP is sufficient to direct the light emitted by a neighboring dipole. Moreover, a single HRID NP has been proposed to be able to reverse this directionality depending on the emission wavelength, and to be able to either collect or reflect the emitted light by tuning the particle-emitter distance. However, those effects have never been demonstrated experimentally, mainly due to the difficulties of placing an individual dipole emitter in the proximity of the NPs with high accuracy. In this work we show that emission directionality can be tuned at the single-molecule level using a single silicon nanoparticle that is deterministically coupled to a single fluorescent molecule using the DNA origami technique. This approach allows manipulation of the emitter's position relative to the Si NP with nanometer precision. By varying the emitter-NP distance, NP size, and fluorescent molecule (and thus emission range), it is demonstrated that a Si NP functions as a broadband directional nanoantenna in the visible range with high robustness to geometrical variations, as opposed to commonly used directional designs. We further show that a displacement of the emitter around the NP can yield to a change in the emission angle (beam steering behavior), which, so far, has only been theoretically predicted. Furthermore, we observed, for the first time with a single nanoparticle, a change in emission direction as a function of the emission wavelength, i.e., color routing, with a strong dependence on the distance between the NP and the emitter. These results represent the first experimental demonstration of beam steering and color routing with a single HRID NP.
Nr: 37
Title:

Single-Molecule Imaging of Peptide Binding on Molecularly Imprinted Polymer Nanoparticles (Invited)
Authors:

Elisabetta Avanzi, Chang Zhou, Alessia Di Fiore, Yannick De Wilde, Karsten Haupt, Ignacio Izeddin and Valentina Krachmalnicoff
Abstract: Single-molecule localization microscopy (SMLM) enabled the investigation of light-matter interactions with nanometric precision. At the Institut Langevin, we developed a microscopy platform that integrates SMLM with fluorescence lifetime imaging (FLIM). This combined approach allows both the detection of individual emitters and the reconstruction of lifetime-resolved super-resolution images, reaching spatial resolutions of about 10 nm and covering time scales from picoseconds to seconds. Such performance provides valuable information on how fluorophores respond to their local nanoscale environment [1-3]. In this work, we used SMLM to characterize biomimetic nanomaterials made from molecularly imprinted polymers (MIPs). These polymer nanoparticles act as synthetic receptors, able to selectively bind target molecules through recognition sites tailored in shape and functionality to the target [4,5]. The MIPs employed here were synthesized via solid-phase polymerization at the Laboratory of Enzyme and Cellular Engineering in Compiègne and fluorescently labeled with fluorescein O-methacrylate (λex 490 nm; λem 520 nm). Their size (~130 nm) and stable fluorescent properties make them suitable for long SMLM acquisitions. In contrast, the target single molecules consisted of peptides labeled with a rhodamine-based far-red fluorescent dye (λex 642 nm; λem 662 nm), and behave as individual emitters, that photobleach after a few emission cycles. This single-molecule behavior makes it possible to resolve and count individual binding events on each MIP. Using our setup, we observed peptide binding to individual MIPs with nanometric precision. The spatial overlap between the peptide emission (excited at 648 nm) and the MIP signal (excited at 488 nm) confirms the specificity of the interaction at the single-particle level. This direct visualization of binding events provides transition from standard ensemble measurements to direct nanoscale observation. Overall the study highlights the potential of SMLM for probing molecular recognition processes in synthetic systems. It offers the basis for future experiments integrating super-resolved fluorescence lifetime imaging to explore the heterogeneity and the kinetics of binding sites, opening new perspectives for the design of next-generation MIP-based biosensors. References [1] A.F. Koenderink et al., Nanophotonics 11, 169–202 (2022). [2] R.M. Córdova-Castro et al., Light: Sci. Appl. 13(1), 7 (2024). [3] R.M. Córdova-Castro et al., submitted (2025). [4] K. Haupt et al., Chem. Rev. 120, 9554–9582 (2020). [5] P.X. Medina Rangel et al., Angew. Chem. Int. Ed. 59, 2816–2822 (2020).
Nr: 38
Title:

Patterned In-Situ Growth as a Platform for Novel Plasmonic Metamaterials (Invited)
Authors:

Pau Vilches Rueda and Leonardo Scarabelli
Abstract: Ordered arrays of metallic nanoparticles provide a versatile platform for plasmonic metamaterials. By leveraging the coupling of the localized plasmonic response of the nanoparticles with the scattering from the ordered array, we have a significant increase in the quality factor of the plasmonic response, overcoming the problems of the single particle approaches. Commonly, these systems are obtained by top-down techniques such as Electron Beam Lithography, but in recent years novel bottom-up strategies have been gaining traction as a scalable and cost-effective alternatives. In here, we show an unconventional wet-chemical bottom-up approach for producing gold nanoparticle ordered arrays. The arrays are obtained by patterning the substrate surface with norepinephrine (PNE) via pressure stamping using a polydimethylsiloxane (PDMS) mold, followed by a fast gold nanoparticle growth step. Using this approach, we can produce particle arrays showing lattice plasmon resonances with quality factors over 70, while avoiding complex equipment and techniques. On top of that, the optical response can be tuned by adjusting the pattern geometry, particle characteristics, and substrate material, all of which significantly influence the localized plasmonic response and can be modified without substantial changes to the fabrication process. Due to the versatility of this process, we can start exploring chemical and/or physical external stimuli to control the growth process. Currently, we are focusing in two approaches. Firstly, we are integrating microfluidics during the growth step, which allows us to mitigate secondary nucleation and modulate growth kinetics through flow rate profiling; this enables us to target new nanoparticle geometries, such as single crystal nanorods. In parallel, we are also exploring the use of light in order to guide the particle growth, varying both color and polarization of the incident electromagnetic wave. Overall, the direct In-situ growth of patterned nanoparticles offers an interesting alternative to other nanofabrication techniques in the production of nanostructured plasmonic metamaterials. It presents a significant advantage in scalability, processing efficiency, and modularity while maintaining strong control over the structural and optical properties. These capabilities open new avenues for fabricating complex plasmonic metasurfaces with potential applications in analytical devices, photocatalysis, and non-linear optics. Previous works: - Vinnacombe-Willson, G. A., Conti, Y., Jonas, S. J., Weiss, P. S., Mihi, A., & Scarabelli, L. (2022). Surface Lattice Plasmon Resonances by Direct In Situ Substrate Growth of Gold Nanoparticles in Ordered Arrays. Advanced Materials, 34(37), 2205330. https://doi.org/10.1002/adma.202205330 - Lonza, M., Vinnacombe-Willson, G. A., Bevilacqua, F., Scarabelli, L., & Liz-Marzán, L. M. (2025). High-Yield In Situ Growth of Supported Gold Nanorods in Microfluidic Channels. ACS Nano, 19(32), 29691-29701. https://doi.org/10.1021/acsnano.5c09672.
Nr: 41
Title:

Optical Properties of Particle Structures Supporting of Anapole States (Invited)
Authors:

Andrey Evlyukhin
Abstract: In this talk, we present a discussion of the realization of anapole states in dielectric and plasmonic structures of various geometries. Before presenting important characteristic results, the difference between the anapole of individual finite structures and the lattice anapole of periodic metasurfaces is discussed. Next, considering anapole states in dielectrics, we present recent results on narrow-band suppression of total electromagnetic scattering, independent of irradiation conditions, by composite dielectric structures (meta-atoms). We then present the latest results on anapole states in planar plasmonic nanostructures optimized for near-field energy enhancement using a topology optimization method. The optimized structures exhibit anapole states with characteristic properties in the visible range, including weak absorption, strong near-field enhancement outside the structure, and strong scattering suppression. We use multipole analysis to elucidate the near- and far-field properties of the anapole state of the nanostructures. Due to the weak coupling in the anapole state, such plasmonic nanostructures, like their dielectric counterparts, act as individual meta-atoms, maintaining their optical response even when used in densely packed metasurfaces and metamaterials.
Nr: 46
Title:

A Novel Chiroptical Spectroscopy Technique (Invited)
Authors:

Jorge Olmos Trigo
Abstract: Chirality refers to the geometric property of objects that cannot be superimposed onto their mirror images. In nature, chirality is ubiquitous; numerous organic molecules, such as glucose, and most biological amino acids, are chiral. In the pharmaceutical industry, chiral specificity is crucial as opposite enantiomers can have vastly different physiological effects depending on their handedness. Enantiomer pairs share the same atomic composition and are indistinguishable when measuring their scalar molecular properties. It is through interactions with other chiral entities so that their chirality can be revealed. In nanophotonics, electromagnetic helicity is the most commonly used chiral entity to unveil molecular chirality. Circular Dichroism (CD) spectroscopy remains the most utilized technique to detect molecular chirality using helicity. In a conventional CD setup, the molecular solution is sequentially illuminated with fields of opposite helicities, and the transmitted power is recorded for each case. The CD signal is then defined as the difference between these power measurements. Despite its widespread use, CD has significant drawbacks. For instance, if CD = 0 at a certain frequency of the electromagnetic field, it becomes indeterminate whether the molecular solution is chiral or not, since CD provides only partial information about molecular chirality. To overcome this limitation, optical rotation (OR) is typically measured, which quantifies the rotation of linearly polarized light as it propagates through a chiral medium. However, both CD and OR are measured in the forward direction, where a dominant achiral background hinders accuracy and reliability. Moreover, CD and OR depend on molecular concentration and optical path length, meaning the signatures are not universal properties of the object. In this work, we introduce a novel spectroscopy technique for characterizing the chirality of dipolar objects based on measuring the Stokes parameters at non-forward angles. The method is universal, avoids achiral background, and is independent of concentration and path length. Additionally, when both enantiomers are present, the technique can determine which enantiomer is dominant. Interestingly, the robustness of this approach can be verified experimentally by measuring the Stokes vector at two different non-forward angles.
Nr: 54
Title:

Electrostatic Repulsion as a Governing Mechanism in Near- and Far-Field Optical Binding of Gold Nanoparticles (Invited)
Authors:

Manuel Marques
Abstract: The dynamics and equilibrium configurations of optically bound particles immersed in a fluid arise from the interplay of multiple physical mechanisms, including optical forces, electrostatic interactions, and hydrodynamic effects [1]. From a theoretical perspective, a key challenge lies in disentangling the relative contribution of these interactions across different length scales. In this work, we combine experiments with a theoretical and numerical framework to demonstrate that short-range electrostatic forces play a central role in determining the observed optical binding configurations. Within our model, electrostatic repulsion between gold nanoparticles is explicitly incorporated and systematically tuned to mimic variations in salt concentration. The theoretical analysis reveals that reducing the strength of the electrostatic interaction favors near-field optical binding, leading to particle arrangements aligned along the polarization direction of the incident field. Conversely, when electrostatic repulsion is dominant, the balance of forces shifts toward far-field optical binding, resulting in equilibrium configurations oriented perpendicular to the polarization direction. Numerical simulations based on this model quantitatively reproduce the experimentally observed particle configurations across the explored parameter space [2]. These results underscore the decisive influence of electrostatic interactions in shaping the energy landscape of optically bound systems, particularly in the regime of far-field optical binding, where repulsive forces critically determine both stability and orientation of the particle assemblies. [1] Boris Louis, Chih-Hao Huang, Marc Melendez, Ana Sánchez-Iglesias, Jorge Olmos-Trigo, Sudipta Seth, Susana Rocha, Rafael Delgado-Buscalioni, Luis M. Liz-Marzán, Manuel I. Marqués, Hiroshi Masuhara, Johan Hofkens, and Roger Bresolí-Obach "Unconventional Optical Matter of Hybrid Metal−Dielectric Nanoparticles at Interfaces" ACS Nano , 18, 32746−32758 (2024) [2] Jim Jui-Kai Chen, Jorge Olmos-Trigo, Boris Louis, Chih-Hao Huang, Susana Rocha, Hiroshi Masuhara, Johan Hofkens, Rafael Delgado-Buscalioni, Roger Bresolí-Obach, Manuel I. Marqués and Marc Mélendez "Tunable Optical Matter: Electrostatic Repulsion Governs Near- and Far-Field Gold Nanoparticle Arrangements" Nanoscale Advances (To be published)
Nr: 57
Title:

Entanglement and Correlations of Photons Emitted by Coupled Organic Molecules (Invited)
Authors:

Ruben Esteban
Abstract: Quantum emitters such as organic molecules can emit photon states of interest for quantum information. For example, a single quantum emitter can emit single photons for quantum cryptography. Further, the interaction between quantum emitters lead to the formation of new hybrid modes, which increases the variety of quantum states that can be generated [1,2]. We discuss the light emitted by two interacting organic molecules, each of them with excitonic losses dominated by spontaneous emission, as it occurs in optimized cryogenic-temperature experiments. We first calculate the intensity correlation g2 of the zero-phonon-line (ZPL) photons emitted from an excitonic state without intervention of vibrational states. A large flexibility to tune the correlations from strongly antibunched to strongly bunched is found by changing the intensity and frequency of the excitation laser [3]. We then discuss the difference between the g2 correlation of the ZPL photons and that of the Stokes photons emitted due to a transition to the first vibrational state. The latter correlation is measured in experiments that agree very well with the theoretical predictions. We also show that, although the generation of a Stokes photon induces the excitation of a very lossy vibration, coherence still plays an important role in the correlations under adequate conditions [4]. Last, we show that, when the two organic molecules have perpendicular dipole moments, a highly entangled state is emitted [5]. Thus, our results highlight that two coupled molecules can emit a very large variety of photonic states. References: [1] Nat. Comm. 13:2962 (2022). [2] Nature Physics 20, 836–842 (2024). [3] Phys. Rev. A 112, 052434 (2025). [4] Phys. Rev. A 112, 052434 (2025). [5] Phys. Rev. Research 6, 023207 (2024).
Nr: 58
Title:

Geometric Antibunching and Nonlinearities in Emitter Lattices (Invited)
Authors:

Antonio I. Fernandez Dominguez
Abstract: In this talk, I will address two related topics in quantum nanophotonics. First, I will analyze the light emission from pairs of quantum emitters embedded in different environments, uncovering the phenomenon of geometric antibunching. This effect arises from directionally dependent interference in the amplitudes of biphoton states, leading to nonclassical photon correlations without relying on intrinsic nonlinearities. Second, I will investigate the emergence of such quantum nonlinearities in perfectly periodic lattices of quantum emitters. In particular, I will discuss the laser-driven excitation of Bloch states below the light cone and the emergence of bistability in the system’s optical response. [1] B. Durá-Azorín, A. Manjavacas, and A. I. Fernández-Domínguez, Phys. Rev. Research 7, 023178 (2025). [2] B. Durá-Azorín, A. I. Fernández-Domínguez, and A. Manjavacas, https://arxiv.org/abs/2510.19992.
Nr: 62
Title:

Transferring Chirality from Light to Matter During Nanoparticle Growth (Invited)
Authors:

Lucas Vázquez Besteiro
Abstract: Light-to-matter chirality transfer can modify achiral plasmonic structures illuminated with circularly polarized light, inducing chiral growth on achiral plasmonic seeds by photocatalytically imprinting the reduced symmetry of the local fields onto the nanoparticle. We will discuss how different energy-transfer mechanisms can drive such asymmetric geometric transformations, discussing recent experimental demonstrations. Plasmonic nanostructures offer strong resonant responses in the UV-to-IR spectral range, which has led to their use in many optical and energy-related applications. Plasmonic photocatalysis stands as a prominent example of the latter, with plasmonic nanostructures serving as nanoscale antennas funneling radiant energy into their local environment. This talk will cover a particular subset of plasmonic photocatalytic setups with two defining characteristics: (i) the light-driven process modifies the geometry of the plasmonic nanoparticle or the optical properties of its immediate environment, and (ii) it does so while preserving local asymmetries induced by the impinging circularly polarized light (CPL). This creates chiral features in initially achiral shapes, hence transferring chirality from light to the nanostructures, and contrasts with common strategies yielding chiral plasmonic systems, where chirality is seeded from molecules or introduced through top-down fabrication methods. The presentation will cover theoretical considerations underpinning light-to-matter chirality transfer in plasmonics, a discussion about the physical energy-transfer mechanisms driving this phenomenon, as well as an overview of experimental work going from pioneering examples to recent progress.
Nr: 64
Title:

Collective Thermal Asymmetry in Plasmonic Colloids for Targeted Photothermal Applications (Invited)
Authors:

Cédric Adelson Bernard Georges Rousseau, Javier Gonzalez Colsa, Pablo Albella Echave, Bjorn Maes and Gilles Rosolen
Abstract: Thermoplasmonic nanoheaters convert light into heat through localized surface plasmon resonances. Most designs are highly symmetric and produce almost isotropic thermal fields i.e. the surrounding medium heats up uniformly, preventing a direction-dependent increase in the temperature. Janus nanoparticles offer a promising alternative by combining materials with very different thermal properties within a single particle [1]. By breaking spatial symmetry, they enable anisotropic heat dissipation and a directional heat flow, commonly referred to as the thermal Janus effect. In photothermal therapy, this directionality could limit overheating healthy tissue while improving efficacy at the target site. Still, the heat produced by an individual nanoheater is constrained by its nanoscale volume, and safety limits on the incident optical power density further restrict the achievable temperature rise. Under these constraints, collective effects in assemblies of nanoheaters could appear promising, as they can increase the total absorbed power while maintaining Janus-driven asymmetry. In our recent work, we investigate the behavior of arrays of Janus nanoparticles. We first study planar arrays and then move to curved arrays to better approximate biologically relevant configurations, such as nanoparticles surrounding a tumor. We show that the Janus effect progressively homogenizes as the number of nanoparticles in the array increases, in agreement with a direct intuitive model. In addition, we disentangle geometric contributions from the thermal-conductivity contributions involved in the Janus factor. Finally, we demonstrate that curvature can increase the spatial extent of the Janus effect.
Nr: 66
Title:

Probing Optical Spin with Circularly Polarized Raman Scattering in Silicon Metasurfaces (Invited)
Authors:

Guillermo Serrera, Rasmus H. Godiksen, Lex M. Dedding, Tom T. C. Sistermans, Ershad Mohammadi, T. V. Raziman, Søren Raza, Pablo Albella and Alberto Curto
Abstract: Nanophotonic metasurfaces are versatile platforms to manipulate light–matter interactions at the nanoscale, with polarization emerging as a particularly powerful degree of freedom [1]. In high-refractive-index dielectric nanostructures, Mie resonances enable strong field confinement and enhancement without the losses associated with plasmonics, making them attractive platforms for spectroscopy and sensing. While polarization control in the far field has been extensively explored, the polarization properties of optical near fields remain difficult to access experimentally. This limitation is particularly relevant for applications such as chiral sensing, where the interaction strength is governed by the local polarization state rather than the propagating field [2]. Raman scattering provides a promising route to probe near-field polarization in dielectric nanostructures. In bulk crystalline materials such as silicon, the polarization of Raman scattering is well described by the Raman tensor and exhibits a predictable response under circularly polarized excitation [3]. However, in nanophotonic resonators the internal field distributions become highly non-uniform and resonance-dependent, potentially altering both the efficiency and polarization state of the Raman emission. Despite extensive work on Raman enhancement in dielectric metasurfaces, the polarization properties of resonantly enhanced Raman scattering—and their connection to the underlying near-field structure—have remained largely unexplored [4]. In this work, we theoretically and experimentally investigate circularly polarized Raman scattering from silicon-on-sapphire disk metasurfaces under circularly polarized excitation in a backscattering geometry. By systematically varying disk diameter, height, and excitation wavelength, we measure both the Raman enhancement factor and the degree of circular polarization (DOCP) of the scattered Raman signal. While certain metasurfaces preserve a relatively high DOCP comparable to bulk silicon, others exhibit a pronounced depolarization despite strong Raman enhancement. Through numerical simulations and multipole decomposition, we identify magnetic and electric quadrupole resonances as the primary origin of this polarization loss. These modes produce complex near-field distributions with spatially varying optical spin, leading to an incoherent mixture of polarization contributions in the Raman emission. Our results establish polarization-resolved Raman scattering as a sensitive and experimentally accessible probe of near-field polarization and optical spin in dielectric nanophotonic systems, with important implications for chiral nanophotonics. REFERENCES [1] J. Mueller et al. Phys Rev Lett 118(2017), 113901. [2] T. V. Raziman et al. ACS Photonics 6(2019), 2583–2589. [3] A. B. Talochkin, J Raman Spectr 51(2020), 201–206. [4] S. Raza and A. Kristensen, Nanophotonics 10(2021), 1197–1209.
Nr: 67
Title:

BIC-Enhanced Partial LDOS in Terahertz Metasurfaces (Invited)
Authors:

Jose Antonio Sanchez-Gil, Jie J, Djero Peeters, Wouter Holman, T. Xuan Hoang, Dook van Mechelen and Jaime Gomez Rivas
Abstract: Near-field terahertz (THz) microscopy is used to directly probe how bound states in the continuum (BICs) enhance the partial local density of optical states (PLDOS) in nonlocal metasurfaces, revealing fundamental limits to BIC-enabled light–matter interaction. Symmetry-protected BICs supported by an infinite array of gold rod dimers remain decoupled from far-field radiation [1], but in finite arrays they manifest as quasi-BICs with finite radiative linewidths whose collective nature governs the PLDOS enhancement. Here, a dual-probe THz near-field time-domain setup, enables direct excitation and detection of quasi-BIC modes and, thus, a direct experimental determination of the PLDOS at the position of the source dipole for defined dipole orientations. This technique has been previously exploited to unveil the symmetry protection of such collective modes in the near field [2], along with the strong confinement perpendicular to the metasurface plane. By comparing measurements on large-area metasurfaces (up to 84 × 84 dimers) to SCUFF-EM boundary-element calculations [4], a strong PLDOS enhancement is observed at the quasi-BIC frequency, highly localized at the rod edges and confined within a subwavelength mode volume [5]. Systematic variation of the array size from a single dimer to multi-dimer arrays shows that the quasi-BIC originates from collective modes whose number and spectral sharpness increase with metasurface size, leading to a diverging quality factor while the PLDOS enhancement saturates at moderate array sizes [4]. This saturation arises from the competition between Q-factor and mode volume, preventing an unbounded increase of PLDOS despite ever-higher Q. Spatially resolved PLDOS maps in the plane and along the out-of-plane direction demonstrate extreme confinement of the enhanced density of states to nanometric regions at the edges of the rods and an evanescent decay away from the metasurface, confirming that quasi-BICs provide both high-Q and deep subwavelength confinement. These results establish an experimental upper limits for BIC-induced LDOS enhancement in realistic finite metasurfaces and define design rules for maximizing on-chip light–matter interaction, with direct implications for THz quasi-BIC engineering. Financial support is acknowledged from Spanish MCIN/AEI/10.13039/501100011033/ and “ERDF A way of making Europe” (LIGHTCOMPAS, PID2022-137569NB-C41). [1] Abujetas, D. R., van Hoof, N., ter Huurne, S., Gómez Rivas, J. & Sánchez-Gil, J. A. “Spectral and temporal evidence of robust photonic bound states in the continuum on terahertz metasurfaces,” Optica 6, 996 (2019). [2] Hoof, N. J. J. V., Abujetas, D. R., Huurne, S. E. T. T. et al. “Unveiling the symmetry protection of bound states in the continuum with terahertz near-field imaging,” ACS Photonics 8, 3010–3016 (2021). [3] ter Huurne, S., Abujetas, D. R., van Hoof, N., Sanchez‐Gil, J. A. & Gómez Rivas, J. “Direct Observation of Lateral Field Confinement in Symmetry‐Protected THz Bound States in the Continuum,” Adv. Opt. Mater. 11, (2023). [4] Reid, M. T. H. & Johnson, S. G. “Efficient computation of power, force, and torque in BEM scattering calculations,” IEEE Trans. Antennas Propag. 63, 3588–3598 (2015). [5] Ji, J., Sánchez-Gil, J.A., Peeters, D. et al., “Near-field probing of the local density of optical states enhanced by bound states in the continuum in nonlocal metasurfaces,” Nat Commun (2025). https://doi.org/10.1038/s41467-025-66653-4.
Nr: 68
Title:

Active and Tunable Metasurfaces for Dynamic Light Emission and Wavefront Control (Invited)
Authors:

Ramon Paniagua Dominguez
Abstract: Metasurfaces hold promise to replicate, and often surpass, the functionality of conventional bulk optics in an ultrathin, lightweight form factor, opening the door to compact and highly integrated photonic systems. These planar optical structures composed of arrays of subwavelength nanoantennas enable precise control over the amplitude, phase and polarization of light. While early metasurfaces were largely passive and static, recent advances have enabled tunable metasurfaces, whose optical response can be dynamically reconfigured. In parallel, light-emitting metasurfaces integrate nanoantennas with active materials to not only shape emitted light with high spatial and spectral control, but also enhance emission efficiency and directionality through tailored light–matter interactions. From interfacing dielectric metasurfaces with liquid crystals and phase-change materials for programmable wavefront control [1,2] to spatiotemporal modulation of non-local metasurfaces enabling ultra-fast energy-momentum transformations [3,4] to novel platforms for dynamic light emission manipulation [5-7], this talk will cover our recent advances in these active fields of research. Financial support is acknowledged from the Singapore’s AME Programmatic Grant A18A7b0058, MTC Programmatic Grant M21J9b0085 and Spanish MCIN/AEI/10.13039/501100011033/ and “ERDF A way of making Europe” (LIGHTCOMPAS, PID2022-137569NB-C41). [1] P. Moitra et al. Electrically Tunable Reflective Metasurfaces with Continuous and Full-Phase Modulation for High-Efficiency Wavefront Control at Visible Frequencies, ACS Nano 17, 16952–16959 (2023) [2] P. Moitra et al. Programmable wavefront control in the visible spectrum using low‐loss chalcogenide phase‐change metasurfaces, Advanced Materials 35, 2205367 (2023) [3] D. A. Shilkin et al. Ultrafast modulation of a nonlocal semiconductor metasurface under spatially selective optical pumping, Nano Letters 24, 14229-14235 (2024) [4] D. A. Shilkin et al. Spatiotemporally Modulated Nonlocal Metasurfaces: Walking the Dispersion Curve, Submitted (2025) [5] J. Tian et al. Phase‐change perovskite microlaser with tunable polarization vortex, Advanced Materials 35, 2207430 (2023) [6] T. C. Meiler et al. Spectral Tuning of Perovskite Laser via Microheaters, Nano Letters 25, 9695–9701 (2025) [7] C. Dong et al. Dynamic Control of Momentum-Polarization Photoluminescence States with Liquid-Crystal-tuned Nanocavities, Adv. Opt. Mater. Accepted (2025)
Nr: 70
Title:

Photothermal and Modulation Effects in VO2/Au Metasurfaces (Invited)
Authors:

Antonio Garcia-Martin
Abstract: Vanadium dioxide (VO2) undergoes a remarkable insulator-to-metal transition at 68°C, accompanied by a drastic, change in electrical resistivity spanning several orders of magnitude. This property has led to its proposed use in photodetectors and uncooled bolometers, exploiting its resistance sensitivity to temperature variations induced by absorbed photons. In this talk we will consider two systems where interaction of VO2 and metallic elements play a key role. In the first, we use orderly arrays of Au nanodisks embedded within VO2 to demonstrate that the insulator-to-metal transition in VO2 thin films is facilitated by plasmon excitation. Direct optical visualization at the submicron scale, when the nanodisks are illuminated near their plasmon resonance with a λ = 1.5 μm laser beam, reveals that the laser power required to induce the transition is reduced by 30% in the presence of Au nanodisks. Using numerical simulations, we explore the underlying mechanisms, finding that the localized dipolar pattern of the electromagnetic field surrounding the nanodisks penetrates deeply into the VO₂, likely acting as the primary driver of the observed modifications in transition conditions [1]. In the second, we consider a perforated thin film placed onto a VO2 unpatterned thin film. We demonstrate that in this system it is possible to achieve reflectance modulations from nearly perfect reflection (90%) down to 10% using simple sub-micron slits patterned into the gold film. This optical-valve effect occurs at discrete wavelengths determined solely by the slit length. The tuning is achieved by temperature variation, acting as the required parameter for external control [2]. References [1] Z. Fang et al., Surfaces & Interfaces 62, 106145 (2025) [2] A. Garcia-Martin, Physical Review Research 7, 023301 (2025)
Nr: 73
Title:

Optical Nonlinearities in Materials with Nonlocal Responses (Invited)
Authors:

Gonzalo Alvarez-Perez
Abstract: Material platforms that support strong nonlocal and nonlinear light–matter interactions are central to the development of mid-infrared (mid-IR) photonic technologies. Among these, heavily doped semiconductors and polar dielectrics are particularly promising systems. They offer high electromagnetic confinement, relatively low optical losses, and tunability of their collective excitations, positioning them as attractive alternatives to noble metals and traditional semiconductors for nonlinear and active photonic applications. In both material classes, collective electronic or ionic excitations give rise to pronounced nonlocal and nonlinear optical responses. In heavily doped semiconductors, the high density of free carriers leads to strong spatial dispersion and nonlinearities that can be accurately described using hydrodynamic theory (HT), which extends the classical Drude model by incorporating quantum pressure, carrier convection, and carrier-density gradient effects. Within this framework, doped semiconductors are predicted to exhibit free-electron nonlinearities exceeding those typically observed in metals and conventional dielectrics [Phys. Rev. B 103, 115305 (2021)]. These predictions have been validated by experiments on third-harmonic generation (THG) in InGaAs nanoantennas, which demonstrated that free-carrier nonlinearities can dominate over lattice-related χ⁽³⁾ contributions [Light Sci. Appl. 14, 192 (2025)]. A key manifestation of nonlocality in doped semiconductors is the existence of longitudinal bulk plasmons—charge-density oscillations that propagate through the bulk and exhibit intrinsic nonlinear behavior. These modes can strongly couple to localized electromagnetic resonances. For instance, coupling longitudinal bulk plasmons to metallic gap plasmons in nanopatch antennas enables strong enhancement of Kerr nonlinearities and ultralow-threshold optical bistability (≈1 mW/µm) [ACS Photonics 11, 4812 (2024)]. Integration into metal–oxide–semiconductor architectures allows dynamic control of the free-carrier density, enabling large plasma-frequency shifts (0.89 µm/V) and reducing bistability thresholds down to 10 µW [Phys. Rev. Appl. 24 (4), 044006 (2025)]. Beyond resonant nanoantennas, nonlocal nonlinearities also provide opportunities for integrated photonics. In all-semiconductor platforms, hybrid waveguides incorporating doped plasmonic layers support long-range hybrid modes with record-high Kerr nonlinearities [npj Nanophotonics 2 (1), 33 (2025)]. When embedded in interferometric architectures, these waveguides enable large power-dependent modulation depths, relevant for all-optical modulation. In polar dielectrics, nonlocal nonlinearities arise from the anharmonic dynamics of optical phonons, where lattice vibrations coupled through long-range Coulomb interactions produce dispersive and intrinsically nonlinear phonon–polariton responses. In nanostructures made from such polar dielectrics, phonon–polariton resonances can similarly amplify nonlinear optical effects through extreme field confinement.
Nr: 75
Title:

Lattice Resonances in Arrays of Time-Modulated Scatterers (Invited)
Authors:

Alejandro Manjavacas
Abstract: Lattice resonances are collective modes in periodic arrays of scatterers, arising from coherent interactions that produce stronger and spectrally narrower responses than those of the individual elements. While well understood in static systems, recent advances in time-varying photonics have opened new avenues for their dynamic control and amplification. In this talk, we will explore lattice resonances in arrays of time-modulated scatterers using a dipolar model combined with Floquet theory, treating each element as a harmonic oscillator with periodically varying optical properties. We will begin by analyzing single-scatterer dynamics to identify the complex eigenfrequencies and show that suitable modulation can suppress losses, enabling amplification. Extending this approach to periodic arrays, we will reveal a rich interplay between temporal modulation and lattice resonances, leading to multi-band amplification at significantly lower modulation strengths. This framework lays the foundation for dynamically tunable lattice resonances, paving the way for ultrafast nanoscale light sources and nonreciprocal photonic devices.
Nr: 76
Title:

Plasmonic Antenna-Emitter Hybrids for Tailoring Single-Emitter Light Emission (Invited)
Authors:

Mario Zapata-Herrera, Luis Montaño-Priede, Nerea Zabala, Ruben Esteban and Javier Aizpurua
Abstract: Plasmonic nanoantennas enable strong confinement of optical fields at the nanoscale by supporting localized surface plasmon resonances arising from collective oscillations of free electrons in metallic nanostructures. This extreme field confinement, occurring in subwavelength volumes, provides a flexible route to engineer the electromagnetic environment experienced by nearby nanoscale objects. As a result, plasmonic nanoantennas have become a key building block in nanophotonics, with applications ranging from enhanced spectroscopy and sensing to the control of light emission at thesingle-emitter level. In this work, we present a systematic theoretical investigation of light emission from single emitters placed in a variety of plasmonic configurations, focusing on three key aspects: i) how single and coupled plasmonic nanoantennas of different geometries modify the emitter photoluminescence through changes in the local density of photonic states (LDOS), including single and dimer gold nanorod antennas, plasmonic nanocavities, patch nanoantennas, and hybrid photonic–plasmonic cavities [1–3]; ii) how the emission spectra of a single molecule can be tailored by positioning it inside a plasmonic nanocavity formed by a gold nanodimer deposited on a mirror substrate, which strongly modifies the local photonic environment and gives rise to very large Purcell factors and Lamb shifts, in good agreement with recent experimental results using DNA-origami–based emitter positioning [4]; and iii) how antenna–emitter hybrid systems can be integrated with dielectric waveguides, such as SiN platforms, to enable efficient coupling of nanoscale emission into photonic circuits [5]. Our results are consistent with recent theoretical and experimental efforts to control emission broadening, energy shifts, and radiative efficiency in metallic nanostructures, and provide a physically grounded basis for nanoscale light-emission engineering. 1. Montaño-Priede. J. L., et al. “An Overview on Plasmon-enhanced Photoluminescence via Metallic Nanoantennas”. Nanophotonics, 13(26): 4771–4794, 2024. 2. Gupta. V., et al., Emission Enhancement of Colloidal Quantum Dots Confined in Double Disc Nano-antennas with Controlled Opening. Nanoscale, DOI: 10.1039/d5nr03524d. 3. Al-Hamadani. A., et al. Photoluminescence Enhancement at Telecom Wavelengths from PbS/CdS Quantum Dots coupled to a Plasmonic Crescent Metasurface. ACS Appl. Nano Mater. 2025, 8, 40,19474–19482. 4. Verlekar, S., et al. Giant Purcell broadening and Lamb shift for DNA-assembled near-infrared quantum emitters. ACS Nano, 19, 3, 3172–3184, 2025. 5. Zapata-Herrera, M. et al. Design Strategies to Optimize Light Emission from Plasmonic Antenna- Emitter Hybrids into Waveguides. In preparation.
Nr: 78
Title:

Control and Detection of Broken Time-Reversal Symmetry and Berry Curvature with Nonlinear Optics (Invited)
Authors:

Giancarlo Soavi
Abstract: Layered materials are an ideal platform to study the interplay between space-inversion and time-reversal symmetries, which can be independently engineered by tuning the number of layers (space-inversion) and via excitation with circularly polarized light (time-reversal). In this talk, I will discuss our recently developed approaches to modulate the bandgap in mono- and bilayer TMDs using ultrafast and off-resonant excitation through the optical Stark and Bloch-Siegert effects, and the possibility to subsequently detect broken time-reversal symmetry using second [1] and third [2] harmonic generation. Finally, I will discuss our recent theoretical [3] and experimental efforts to link the resonant linear and nonlinear optical response of crystals to their momentum local Berry curvature. References 1. Herrmann, P. et al., “Nonlinear valley selection rules and all-optical probe of broken time-reversal symmetry in monolayer WSe2”, Nat. Photon. 19, 300 (2025). 2. Friedrich F. et al., “Measurement of optically induced broken time-reversal symmetry in atomically thin crystals”, Nat. Photon. DOI: https://doi.org/10.1038/s41566-025-01801-2 (2025). 3. Soavi, G. and Wilhelm, J., “The role of Berry curvature derivatives in the optical activity of time-invariant crystals”, arXiv:2501.03684 [cond-mat.mes-hall], (2025).
Nr: 79
Title:

Measuring Temperature Gradients with Nanometer Resolution Combining DNA-PAINT and DNA Origami Nanotechnology (Invited)
Authors:

Guillermo Pedro Acuna
Abstract: Plasmonic nanoparticles (NPs) are widely used in various research fields due to their ability to efficiently convert light into heat. This property is exploited in applications such as photothermal therapy or controlled drug release, where plasmon-induced heating is the primary objective. However, in other contexts this heating can have an undesired effect. In biomedical applications, for instance, it is crucial to precisely control the generated heat, as it can alter molecular interactions or damage biomolecules. In all these cases, it is essential to have reliable methods to measure temperature and thermal dissipation at the nanoscale. Current methods based on temperature-sensitive luminescent probes have limitations: they collect signals from a focal volume and are restricted by the diffraction limit of light, which reduces their spatial resolution and temperature measurement accuracy.¹ The present plan aims to address nanoscale thermal measurement challenges using DNA-PAINT super-resolution microscopy, combined with DNA origami technology. This approach takes advantage of the fact that the hybridization kinetics of complementary DNA depend on temperature, enabling precise estimation of kinetic constants from the binding times between strands. DNA origami nanostructures were engineered as nanoscale platforms to position three “nanothermometers” (groups of single-stranded DNA) with nanometer precision around plasmonic gold nanorods serving as localized heat sources. The binding kinetics of these sites, which span distances between 20 and 95 nm from the nanorod surface, were analyzed to determine the local temperature. We performed calibrations on the three docking sites by analyzing the distribution of ON times at different temperatures. These distributions were fitted using single exponential functions, and the obtained ON times were used to build an Arrhenius plot for each site. With this, we were able to measure temperature changes at the nanometer scale after heating the gold nanorods with light. Our method provides a new and robust platform to measure temperature changes with high spatial resolution. Given the versatility of nanoparticles functionalization and of the DNA origami technology, other nanostructures can be placed instead of the nanorods used in this study, and temperature changes can still be measured with high precision and spatial accuracy. References [1] Martinez, L. P. et al. Thermometries for Single Nanoparticles Heated with Light. ACS Sens 9, 1049–1064 (2024).
Nr: 82
Title:

Large-Area All-Silicon Infrared Metaoptics (Invited)
Authors:

Otto Muskens
Abstract: Recent years have seen the emergence of metasurface optics, or metaoptics, from the laboratory and into consumer applications. Methods for reproducible manufacturing of metaoptics leveraging the capabilities of advanced semiconductor processing are of particular interest. Here I will present our recent results on wafer-scale fabrication of all-silicon metaoptics using the University of Southampton’s cleanroom [1]. In a new process, deep-UV lithography is applied on both sides of the wafer, allowing monolithic fabrication of double-sided metalens elements. This approach was successfully applied to the realization of dual-band metaoptics covering both mid-wave and long-wave infrared spectral bands. [1] K. Sun, X. Yan, J. Scott, J. Y. Ou, J. N. Monks, O. L. Muskens, Production-ready double-side fabrication of dual-band infrared meta-optics using deep-UV lithography, ACS Nano 19, 42, 37218 (2025)
Nr: 84
Title:

Space-Time Image Processing in Nonlinear and Nonlocal Metasurfaces (Invited)
Authors:

Costantino De Angelis
Abstract: Digital signal processing has revolutionized many fields of science and engineering, but it still shows critical limits; a long-sought solution is optical analog computing. We demonstrate here that nonlinear phenomena combined with engineered nonlocality in flat optics can be leveraged to synthesize Volterra kernels able to outperform linear devices. In this work, I will present our recent findings on the use of nonlocality and nonlinearity for image processing in space and time.
Nr: 85
Title:

Polaritons as a Photonic Testbed for Advancing Organic Optoelectronics (Invited)
Authors:

Konstantinos Daskalakis
Abstract: Strong light–matter coupling has recently emerged as a powerful tool for advancing organic optoelectronics. Polaritons have been shown to modify intramolecular photophysical rates, suppress exciton–exciton annihilation, and enhance charge and energy transport—effects directly relevant to improving light-emitting and light-detecting devices. In our recent theoretical work, we established a comprehensive model describing how strong coupling influences reverse intersystem crossing and triplet–triplet annihilation beyond the single-excitation subspace, capturing processes that limit OLED efficiency. [1]. Experimentally, we realized fully solution-processed all-dielectric microcavities with Rabi splittings exceeding 400 meV and strong polariton photoluminescence [2]. These structures exhibit a tenfold suppression of singlet–singlet annihilation relative to bare films, showing that cavity-induced modifications of molecular relaxation can be engineered through optical design. Building on these insights, we applied strong coupling in non-fullerene acceptors to develop the first narrowband near-infrared polariton organic photodiode (OPD) combining angle-independent response within ±45° and record responsivity of 0.24 A/W at 965 nm [3]. Together, these works demonstrate that polaritonics provides a versatile photonic testbed for optimizing molecular materials and device architectures, offering a new route to high-performance and spectrally precise organic infrared optoelectronics. 1. Siltanen et al., Adv. Opt. Mater., 10.1002/adom.202403046* (2025) 2. Qureshi et al., Adv. Opt. Mater., 10.1002/adom.202500155* (2025) 3. Abdelmagid et al., Adv. Opt. Mater., 10.1002/adom.202501727* (2025).
Nr: 90
Title:

Next-Generation Photothermal Agents: A Study on DNA-Templated and Polymer-Based Janus Systems (Invited)
Authors:

Pablo Albella and Javier González-Colsa
Abstract: Plasmonic nanoparticles (NPs), known for their strong light–matter interactions through Localized Surface Plasmon Resonances (LSPRs), enable the efficient conversion of optical energy into heat, performing as nanoheaters, a central phenomenon in thermoplasmonics [1,2]. While often regarded as a limitation in biosensing, this effect becomes an asset in applications requiring localized heating, such as photothermal therapy (PTT) [3]. However, conventional single material nanoheaters typically produce isotropic heat distributions, posing risks of non-selective tissue damage [4]. Here, we first discuss advanced thermoplasmonic nanostructures, focusing on hybrid systems, to address the need for directional and tunable heating. Then, building on these findings, we explore toroidal gold nanostructures as promising platforms for achieving anisotropic heating and DNA-templated core–shell nanotoroids as a feasible technique for its fabrication [4, 5]. To bridge theory with application, we model a more experimentally accessible system: hybrid polymersomes embedding ultra-small AuNPs within their membranes. These structures exhibit excellent colloidal stability and enhanced cellular uptake. Controlled gold loading within the polymer matrix enables superior thermoplasmonic performance, with experimentally validated temperature rises exceeding 10 K in aqueous dispersions [6]. Our integrated theoretical–experimental approach lays a robust foundation for the rational design of next-generation nanoplatforms for targeted photothermal therapy, emphasizing the importance of hybrid material systems and precise thermal modeling.
Nr: 93
Title:

Reversible Strain Control of Quantum Emitters in 2D Semiconductors (Invited)
Authors:

Julia G. Prieto
Abstract: In recent years, atomically thin semiconductors based on transition-metal dichalcogenide (TMD) monolayers have emerged as a versatile platform for solid-state quantum emitters (QEs), combining exceptional optical quality with intrinsic mechanical flexibility [1]. This remarkable stretchability allows their optical response to be tuned over a wide range through elastic strain engineering [2]. Alt-hough the microscopic origin of QEs is still under active investigation, limiting the deterministic fab-rication of identical emitters, it is widely accepted that their formation is closely linked to local strain fields and lattice defects. Position-controlled QEs can thus be realized by introducing static strain gra-dients via nanoscale features such as pillars or bubbles, which funnel excitons into localized regions where quantum light emission occurs [3]. Here, we present our recent results on the reversible tuning of the emission energy and brightness of QEs in WSe₂ monolayers. This control is achieved using a hybrid semiconductor–piezoelectric plat-form, in which the monolayer is integrated onto piezoelectric nanopillars that generate both static and dynamic strain fields. By combining numerical simulations with exciton drift–diffusion modelling, we demonstrate that these strain fields reshape the confining-potential landscape, leading to a reversible redistribution of excitons among individual emitters [4]. Finally, we present complementary high-resolution optical and structural characterization at the nanoscale, which provides a quantitative map-ping of the static strain in nanobubbles, a key aspect in the formation of QEs in TMD monolayers. References [1] Y.-M. He et al. Nat. Nanotechnol., 10, 497 (2015); P. Tonndorf et al., Optica, 2, 347 (2015); A. Srivastava et al., Nat. Nanotechnol., 10, 491 (2015). [2] Zhaohe Dai et al. Adv. Mater., 31, 1805417 (2019); Zhiwei Peng et al. Light: Sci. Appl., 9, 190 (2020). [3] A. Branny et al., Nat. Commun., 8, 15053 (2017) ; C. Palacios-Berraquero et al., Nat. Commun., 8, 15093 (2017). [4] G. Ronco et al., npj 2D Mater. Appl. 9, 65 (2025).
Nr: 94
Title:

Canalization-Based Super-Resolution Imaging Using an Individual van der Waals Thin Layer (Invited)
Authors:

Aitana Tarazaga Martín-Luengo
Abstract: Canalization is an optical phenomenon that enables unidirectional light propagation without predefined wave guiding designs. In van der Waals (vdW) polaritonic platforms, canalization has been demonstrated in twisted α-MoO3 bilayers and trilayers, but applications have been limited by fabrication complexity and the need for precise twist-angle control [1-5]. In this work [6], we propose theoretically and demonstrate experimentally a previously unexplored canalization phenomenon for phonon polaritons (PhPs) that takes place in single individual, unstructured, pristine α-MoO3 layers when placed on a substrate with a given negative permittivity. The inherent ease of implementation, low-loss nature (PhPs lifetimes of ~2 ps), and broad spectral coverage (~50 cm-1) of this single-layer canalization allow us to introduce a first proof-of concept application based on this phenomenon: nanoimaging of buried nanostructures. A single α-MoO3 layer on SiC functions as a near-field hyperlens (or equivalently, a laterally shifting superlens), transferring subwavelength near-field information to the top surface. Experiments on arrays of buried Au nanodisks resolve edge-to-edge separations down to ~50 nm at λ_0=11.3 μm, corresponding to a deep sub-diffraction resolution of ~λ_0/220. Importantly, this imaging scheme transcends conventional projection constraints, allowing super-resolution images to be obtained at any desired location in the image plane by manipulating parameters such as the incident frequency, the rotation angle of the thin layer, and its thickness. Although demonstrated using SiC, our results can be generalized to many other substrates whose metallic properties are tunable, such as graphene, doped semiconductors, or phase change materials. Together, our results thus open avenues for integrated flat optics, nanoscale information transfer, and heat management applications using highly collimated PhPs.
Nr: 97
Title:

Transition from Far-Field to Enhanced Near-Field Radiative Heat Transfer in a Multi-Body System Involving Two Microspheres (Invited)
Authors:

Ana Isabel Fdez.-Tresguerres Mata and Yannick De Wilde
Abstract: Thermal radiation is responsible for heat transfer between bodies in vacuum. In the far-field regime, when object dimensions and separations are large compared to the thermal wavelength, a well-defined limit exists, known as the blackbody limit and described by Planck’s radiation law. However, at micrometric or nanometric length scales below the thermal wavelength, this description breaks down and new physical mechanisms become dominant. In this near-field regime, radiative heat transfer can be mediated by evanescent fields, enabling it to surpass the blackbody limit [1]. While radiative heat transfer in the sphere-plane geometry has recently been revisited in our group [2], this work presents a novel experimental study investigating radiative heat transfer between multiple bodies within a two-sphere geometry. We use two silicon dioxide microspheres of various diameters supporting localized surface phonon polaritons. These excitations play a central role in near-field heat transfer. A highly sensitive platform based on thermoresistive probes combined with Wheatstone bridges enables the detection of very small resistance changes associated with minute temperature variations, as well as precise control of the sphere separation from micrometers down to nanometers, allowing investigation of the transition from far- to near-field regimes. In this way, we directly probe radiative exchange in a multi-body system where the surrounding environment plays a significant role. Results with microspheres of various diameters reveal a strong modification of near-field radiative heat transfer, dominated by localized surface polaritonic modes that significantly enhance energy exchange. Two independent thermal probes in our setup enable one to find where exactly radiative heat flows between the bodies involved in the system. Our findings highlight fundamental differences between far- and near-field radiative heat transfer and demonstrate the importance of near-field effects for achieving control over thermal radiation at the nanoscale.