AOMatDev 2025 Abstracts

Area 1 - Advanced Optical Materials and Devices
Short Papers

Area 1 - Advanced Optical Materials and Devices

Nr: 87
Title:

Fast and Low-Cost Prototype for E. coli Detection Using Liquid Crystal Optical Sensors
Authors:

Maria Simone Fernandes Soares, Francisco Gameiro, Nuno Santos, Pedro Almeida and Carlos Marques
Abstract: In the food production sector, quickly identifying potential hazards is crucial due to the resilience of many pathogens, which could lead to wasted production results and more severely, epidemic outbreaks. E. coli monitoring is essential, though traditional quality control methods in fish farming are often slow and intrusive promoting an increase in fish stress and mortality rates. This paper presents an alternative method by utilizing a prototype inspired by Polarized Optical Microscopy (POM), constructed with a Raspberry Pi microprocessor to assess pixel patterns and calculate analyte levels. The sensors are based on the immune complexation reactions between E. coli-specific antibodies and the disruption of Liquid crystals (LC) alignment, which is measured with the POM technique. The prototype yielded a sensitivity of 1.10 ± 0.17 %/𝑙𝑜𝑔10(CFU/ml) for E. coli. In this paper, tests using sunlight as the prototype’s light source were also performed, and a user-friendly Graphical User Interface was designed.
Nr: 110
Title:

Optical Fiber-Based Interrogation Setup: An Easy Method to Measure the Desorption Ativation Energies of Molecules in Liquid Media
Authors:

Maria Raposo, Catarina Monteiro, Susana Sério, Susana Silva, Paulo António Ribeiro and Orlando Frazão
Abstract: The development of reproducible sensors of biological molecules at low concentrations in liquid media, usually based on self-assembly and layer-by-layer (LB) thin films, strongly depends on desorbing the molecules physically adsorbed on a surface as a thin film. The most adequate method to measure the desorption activation energy values is to use thermally activated desorption in liquid. However, spectrophotometric methods are necessary to analyze the adsorbed amount of a molecule on a surface. These methods make the procedures to find the desorption activation energy values slow and laborious. However, the optical fiber-based interrogation setup to analyze the desorption of molecules from surfaces can be the solution to become a fast and reliable method to study the desorption of molecules from a solid surface when immersed in a liquid medium. In this presentation, one intends to demonstrate the proof of concept using layer-by-layer (LbL) films of polyethyleneimine (PEI) and graphene oxide (GO) film layers deposited on an optical fiber surface as an easy method to measure the desorption activation energy of molecules adsorbed on surfaces. Results allowed us to conclude that the desorption activation energy of GO from the PEI layer takes a value of about 120 kJ/mol which is easily related to the ionic interactions between GO and PEI polyelectrolyte molecules. Results achieved with other polyelectrolyte molecules will be also presented.
Nr: 112
Title:

Materials as Enablers of Structured Light: A Review of OAM Generation Through Advanced Material Systems
Authors:

Temitope M. Olaleye, Maria Raposo and Paulo António Ribeiro
Abstract: Over the past two decades, structured light carrying orbital angular momentum (OAM) has revolutionized fields such as optical communication, quantum computing, imaging, and sensing. Its helical phase structure enables unique data encoding and light-matter interactions, making it critical for next-generation photonic technologies. While spatial light modulators (SLMs) have been pivotal in generating and controlling OAM, their reliance on bulky setups and limited scalability underscores the need for material-based alternatives. This review examines advanced materials—such as 2D systems like graphene, azobenzene-based polymers, organic chiral compounds, metal nanoparticles, magnetic materials, and perovskites—as promising solutions for tunable, efficient OAM generation and manipulation at micro- and nanoscale levels. These materials offer unique optical, chiral, and nonlinear properties, paving the way for compact, integrated OAM systems compatible with photonic and optoelectronic platforms. We analyse their mechanisms, performance, and potential to address current challenges, aiming to foster innovations that expand the structured light research and applications ecosystem.
Short Papers
Paper Nr: 5
Title:

Optical Fiber Probe Based on Localized Surface Plasmon Resonance of Gold Nanostructures for Chemical Sensing
Authors:

Amin Moslemi, Lucia Sansone, Flavio Esposito, Carlos Marques, Stefania Campopiano, Michele Giordano and Agostino Iadicicco
Abstract: In this study, we present an experimental investigation of highly sensitive optical fiber sensors utilizing localized surface plasmon resonance (LSPR), achieved by depositing gold nanoparticles (NP) onto uncladded silica multi-mode fiber. This setup takes advantage of the unique optical characteristics of optical fiber sensors and plasmonic resonance provided by gold NPs. The experimental results demonstrated a maximum sensitivity of about 130 nm/RIU in water solution, for an LSPR wavelength at 560 nm. As a study case, the sensor was used to detect Thiram, a common agricultural pesticide, exhibiting a wide detection range from 10 nM to 100 µM, with a significant wavelength shift up to 4 nm. Moreover, a preliminary study involving the use of nanostar-based optical fiber sensors is comparatively provided. The highest sensitivity makes this approach highly promising for a range of applications, including environmental monitoring, biomedical diagnostics, and chemical detection.
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Paper Nr: 6
Title:

Comparative Analysis of Mechanically Induced Long Period Gratings Using Different 3D Printed Grooved Structure Shapes
Authors:

Sidrish Zahra, Elena De Vita, Flavio Esposito, Agostino Iadicicco and Stefania Campopiano
Abstract: This study deals with mechanically induced long period fiber gratings (MILPGs). First, an in-depth analysis of the most effective grating configuration of a grooved structure featuring a duty cycle of 40:60 using SMF-28 is provided. Subsequently, a comparative analysis of MILPGs developed in various multi-layered optical fibers, including double cladding fibers with doped and pure-silica core as well as solid core photonic crystal fiber is presented. The demonstrated fabrication method highlights its adaptability for various types of fibers, eliminating the need for supplementary equipment or modifications, and operates independently of photosensitive fibers which marks the novelty of this work.
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