PHOTOPTICS 2022 Abstracts

Area 1 - Lasers
Full Papers Short Papers
Area 2 - Optics
Full Papers Short Papers
Area 3 - Photonics
Full Papers Short Papers

Area 1 - Lasers

Full Papers
Paper Nr: 23
Title:

Deployment of 1610 nm InAs/InP Quantum-dash Laser Diode in 28–50 GHz Hybrid RoF-RoFSO-Wireless Transmission System
Authors:

M. M. Khan
Abstract: In this paper, we report on our recent demonstrations on deploying mid L-band ~1610 nm quantum-dash (Qdash) laser diode (LD) in millimeter-wave (MMW) applications. 28 and 30 GHz MMW beat-tones are generated using a self-injection-locked (SIL) Qdash LD-based comb source (QDCS) with phase noise of ~-120 dBc/Hz at 1MHz offset frequency. Moreover, we demonstrated transmission of these MMWs over various channels comprising of single-mod-fiber (SMF), generally known as radio-over-fiber (RoF), free-space-optics (FSO), known as radio-over-FSO (RoFSO), and wireless (WL) links, which are attractive solutions for future flexible next-generation access networks (NGANs). In particular, we demonstrated successful transmission of 28 and 30 GHz MMW modulated with analog 2 Gb/s quadrature-phase-shift-keying (QPSK) data over hybrid 20 km SMF – 5 m FSO and 0- 6 m WL channel. Moreover, we also discussed our very recent preliminary results of 50 GHz high-frequency generation and transmission utilizing QDCS. In this case, we showed error-free transmission of 2 Gb/s QPSK data over 50 GHz carrier and 11.6 km SMF – 6 m FSO and 0-1 m WL channel. This rule-changing broad multi-wavelength lasing spectrum from Qdash LD and emission covering S- to U-band has made it a prime contender for NGANs.
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Short Papers
Paper Nr: 24
Title:

Comparative Study of Two Approaches for Application of Terrestrial Laser Scanner in Structural Health Monitoring and Damage Assessment
Authors:

Shakhzod M. Takhirov
Abstract: The main objective of the paper was to evaluate two approaches aimed at tracking small displacements. The first approach is based on the usage of laser targets commonly used for stitching point clouds together. The second approach is based on the estimation of a corner of a prismatic shape and utilizes thin horizontal slices of the shape’s point cloud. The corner’s location is estimated as an intersection of two straight lines best fitted to the point clouds before and after the corner. It was shown that for both approaches a sub-millimetre accuracy can be achieved. The first approach requires the installation of two laser targets in order to measure the change of the distance between them. The second approach offers more flexibility because it does not require the installation of a laser target. Hence it can be used in the quantitative assessment of structural damage in the aftermath of natural disasters such as earthquakes, fires, tsunamis, landslides and hurricanes, to name a few.
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Paper Nr: 25
Title:

Comparison of Different Grating Structure DFB Lasers for High-speed Electro-absorption Modulated Lasers
Authors:

Siti Sulikhah, San-Liang Lee and Hen-Wai Tsao
Abstract: High-speed electro-absorption modulated lasers (EMLs) with three DFB laser structures (uniform grating (UG), asymmetric quarter-wave-shifted (QWS), and partially corrugated grating (PCG)) are investigated here under 56-Gb/s NRZ signal modulation. It is known that the former UG-EML suffers from performance degradation due to the residual facet reflection (RFR) and facet phase fluctuation. PCG-EML with 300-µm long laser section, 175-µm long grating section, 100-µm long modulator section, and 10-3 front-facet reflectivity can produce about ~83.8% dynamic single-mode yield (SMY), improved average Q-value, and reduced low-frequency drop (LFD) in the modulation response. By choosing the optimal grating length for the PCG-DFB and applying an asymmetric QWS-DFB, the EMLs can maintain good static- and dynamic performances over a wide range of the linear gain coefficients.
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Area 2 - Optics

Full Papers
Paper Nr: 3
Title:

Study of Three WFS for the Modular System in a Portable AO Instrument: ALIOLI
Authors:

Esther Soria and Roberto López
Abstract: Adaptive optics (AO) systems correct atmospheric turbulence in real time and they are normally designed for large telescopes but not for modest due to their cost. In this paper, we propose a portable AO instrument, named ALIOLI, capable of be installed in different medium and small-sized telescopes. The novelty of this new instrument is the modularization of its components which allows great flexibility in the design, being possible easily adapt the instrument to the working telescope or observing technique by adjusting each module independently. Here we present the instrument concept and a preliminary design for its installation in the Carlos Sanchez Telescope (! 1.5m, Teide Observatory (Canary Islands)). The Wavefront Sensor (WFS) module is intended to be used with three different WS, Shack-Hartmann, Two Pupil Plane Position and non-modulated Pyramidal, allowing a joint configuration for comparative studies. A comparison of the response of these sensors has been carried out by simulating the instrument in Python. The simulation results demonstrate the goodness of the applied algorithms and the higher linearity and precision of the SH WFS in comparison with the others two.
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Paper Nr: 4
Title:

Combining a Grayscale Camera and Spectrometers for High Quality Close-range Hyperspectral Imaging of Non-planar Surfaces
Authors:

Stefan Lörcks and Josef Pauli
Abstract: In recent years, hyperspectral imaging (HSI) has emerged to become a crucial method for both remote sensing and close-range surface analysis. In this paper, we present substantial upgrades of our previously published system for multispectral and hyperspectral surface analysis (Hegemann et al., 2017). Besides minor changes in illumination, we carefully evaluated different approaches for reflectance correction using up to eight calibration standards. Wavelength correction, which ensures an exact wavelength fit, is also done using a calibration standard. Therefore, our calibration pipeline provides high-quality hyperspectral data that is mostly independent of the hardware acquiring it, as we remove the impact of illumination and sensor sensitivity and consequently solely dependent on the sample. Additionally, as the main contribution, we present a method to acquire hyperspectral images from a non-planar surface using spectrometers without a time-consuming auto- focus at every pixel position. We do this by generating a registered depth map from gray value images of the sample. Since annotated hyperspectral data is in high demand, we also contribute two initial pixel-wise labeled close-range hyperspectral datasets generated with our upgraded system for further research and benchmarks.
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Paper Nr: 8
Title:

Native Ethernet Optical Switching for Deterministic Critical Networks
Authors:

Brice Leclerc, Olivier Marce, Bogdan Uscumlic and Dominique Chiaroni
Abstract: In this paper we present a novel approach enabling the switching of native Ethernet frames directly in the optical domain without any buffering. This is possible for the first time in the optical domain thanks to our approach using the known Ethernet frames arrival times, to preconfigure the fast-optical switches to build a new optical path before arrival of the Ethernet packet. The technique is analysed and validated with an Ethernet frame analyser to demonstrate its feasibility.
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Paper Nr: 14
Title:

Classification of Brain Tumour Tissues in Human Patients using Machine Learning
Authors:

Françoise Bouvet, Hussein Mehidine, Bertrand Devaux, Pascale Varlet and Darine A. Haidar
Abstract: Delineating brain tumor margins as accurately as possible is a challenge faced by the neurosurgeon during tumor resections. The extent of resection is correlated with the survival rate of the patient while preserving healthy surrounding tissues is necessary. Real-time analysis of the endogenous fluorescence signal of brain tissues is a promising technique to answer this problem. Multimodal optical analysis has been proved to be a powerful tool to discriminate tumor samples of different grade of gliomas and meningiomas from healthy control samples. In this study, Machine Learning methods are evaluated to improve the accuracy of such discrimination. Each sample is described by 16 feature given in input to a Decision Tree based model. Once the learning step is completed, the classifier achieves a 95% correct classification on unknown samples. This study shows the potential of Machine Learning to discriminate between tumoral and non tumoral tissues based on optical parameters.
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Paper Nr: 16
Title:

Exploring the Tabu Search Algorithm as a Graph Coloring Technique for Wavelength Assignment in Optical Networks
Authors:

Inês Gomes, Luís Cancela and João Rebola
Abstract: The aim of this work is to study the Tabu Search algorithm as a graph coloring technique for wavelength assignment in optical networks, a crucial function in optical network planning. The performance of the Tabu Search is assessed in terms of the number of wavelengths and computation time and is compared with the one of the most common Greedy algorithm. It is concluded that for real networks with a large number of nodes and a higher variance node degree of the path graph relatively to its average node degree value, the Greedy algorithm is preferable to the Tabu Search algorithm since it returns the same number of colors of Tabu Search, but in a shorter computation time.
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Paper Nr: 20
Title:

Multiphoton Microscopy for Bacterial Imaging: A Label-free Solution Resting on Endogenous Two-photon Fluorescence
Authors:

Cédric Delmon, Erwan Ferrandon, Emilie Chouzenoux, Audrey Prorot, Sophie Alain and Claire Lefort
Abstract: We demonstrate the interest of multiphoton microscopy (MPM) for imaging bacteria without any labelling process. Six families of bacteria are tested: Escherichia coli, Staphylococcus epidermidis, Proteus vulgaris, Pseudomonas fluorescens, Bacillus subtilis and Clostridium perfringens. For each of these bacteria, the image of a cell is recorded through a multiphoton microscope thus revealing the 3D shape of these bacteria. For the first time, the images of such bacteria are recorded without any labelling solution. A protocol of controlling the image produced is led thanks to a standard staining protocol with carboxy fluorescein diacetate (CFDA) for E. Coli and Staphylococcus epidermidis. Similar object shapes with or without labelling are produced, thus validating the label-free images generated by MPM. Then, the two-photon excitation spectra are measured for each of these bacteriaand the emission spectra delivered by E. Coli and Bacillus subtilis are shown. The origin of the two-photon fluorescence (TPF) emission of the bacteria thanks to the nonlinear imaging solution is discussed regarding to the TPF excitation and emission spectra of metabolic indicators.
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Short Papers
Paper Nr: 1
Title:

OTDR based Estimation of Optical Fiber Link Residual OFDM CFO
Authors:

Adriana Lipovac, Vlatko Lipovac, Mirza Hamza and Vedran Batos
Abstract: Optical time-domain reflectometer (OTDR) has long been and is still considered the main test tool for characterizing fiber optic links, i.e. identify and localize refractive and reflective events such as breaks, splices and connectors, and measure their insertion/return loss. Specifically, sufficient dynamic range and thus alike signal-to-noise-ratio (SNR) enable clear far-end visibility even of long fiber links. Moreover, under such conditions, the highest achievable optical bit-error-rate (BER) floor is to the large extent determined by major reflective events such as the specific trace distortion caused by connectors and splices, each with significant return loss. Realizing this has provided the opportunity window to extend the standard OTDR capabilities list by the appropriate trace postprocessing to predict the BER floor. Accordingly, considering the SNR high, and thereby the inter-symbol interference dominant error generating mechanism, we applied the time-dispersion channel model that determines the BER floor by the rms delay spread of the (fiber) channel power-delay profile. We verified the BER floor prediction in the exemplar practical test situation, by measuring the actual BER on the same fiber link, and found the obtained values well matching the OTDR - based predicted ones. Furthermore, when no dominant reflective events are identified on the OTDR trace, it implies very small time dispersion allowing the OFDM symbol cyclic prefix to always prevent inter-symbol interference. This retains the CFO to solely determine the residual BER floor and vice versa, enabling indirect estimation of CFO-induced phase distortion by simple BER testing. With this regard, we abstracted CFO with the AWGN being justified by the Central Limiting Theorem to enable efficient and quite accurate short-term BER (and so CFO phase error) predictions.
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Paper Nr: 2
Title:

Integration of Downlink Scheme VLC Access Techniques for Low-cost Implementation Indoor Communication System: A Survey
Authors:

Hikmatyarsyah and Sasono Rahardjo
Abstract: Integration of Visible Light Communication (VLC) system to Power Line Communication (PLC) or Ethernet (PoE) in terms of channel gain are introduced. The paper proposes the efficient system after comparison in terms of cost installation as a substitute for the use of optical fiber as a transmission media for this hybrid system to adopt early in the in-building coverage as a potential candidate to replace the radio-based traditional indoor system (DAS system) for low-to-medium transmission as commonly refer as small-cell. The downlink scenario has been chosen to apply with each different advantages and disadvantages of these hybrid technologies. In this paper, we provide a survey of each hybrid channel gain model with the introduction of input-dependent and input-independent noise to the input signal with data rates as the output with the error measurement of bit error rate (BER) using common optical single or multi-carrier modulation. After comparison, we can conclude that hybrid VLC with PLC as the network backhauling has the advantage in terms of already-existed facility and easy-installment for an external adapter and this hybrid system tends to applied lower LED power consumption even though achieved lower data rates making this hybrid system has full potential to be applied in the near future.
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Paper Nr: 5
Title:

Analysis of Optimal Polarization State Sampling Frequency Applied to Photoelastic Analyzer
Authors:

Chih-Chung Yang, Chih-Ning Hsu, Yi-Yung Chen, Yu-Hsuan Lin, Hsin-Yi Tsai, Kuo-Cheng Huang and Chun-Han Chou
Abstract: In the paper, we proposed a low-cost photoelastic analysis system and used this system to measure the stress distribution of the doublet lens. The doublet lens was measured by four types of sampling frequency. The sampling frequency was 45 degrees, 22.5degrees, 11.25degrees and 5degrees. The different sampling frequency data was used to build a chart which was the relationship between measurement error and sampling frequency. The chart could help who used the method to choose a suitable sampling frequency and establish the most efficient process of stress measurement. In the future, we hope to improve the photoelastic analysis system to be fully automatic and apply it in the factory production line.
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Paper Nr: 6
Title:

Eigenvalue and Eigenvector Expansions for Image Reconstruction
Authors:

Tomohiro Aoyagi and Kouichi Ohtsubo
Abstract: In medical imaging modality, such as X-ray computerized tomography, image reconstruction from projection is to produce the density distribution within the human body from estimates of its line integrals along a finite number of lines of known locations. Generalized Analytic Reconstruction from Discrete Samples (GARDS) can be derived by the Singular Value Decomposition analysis. In this paper, by discretizing the image reconstruction problem, we applied GARDS to the problem and evaluated the image quality. We have computed the condition number in the case of changing the views and the normalized mean square error in the case of changing the views and the number of the eigenvectors. We have showed that the error decreases with increasing the number of eigenvectors and the number of views.
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Paper Nr: 10
Title:

BER based Assessment of Spectral and Energy Efficiency in a Two-tier Heterogeneous Network
Authors:

Jasmin Musovic, Adriana Lipovac and Vlatko Lipovac
Abstract: In this paper, we analyze an arbitrary heterogeneous cellular network applying stochastic geometry, and propose a modified model for assessing network spectral and energy efficiency. With this regard, we recognize that, in practice, determining Signal-to-Noise-and-Interference Ratio (SINR) as the key performance indicator, requires complex field test equipment, which might not be available or affordable. Therefore, we propose here a simple model that is based on the relatively easy measurable Bit-Error Rate (BER), whose degradation caused by various impairments is considered here as if it was due to the according additive white Gaussian noise (AWGN), thus abstracting any specific non-AWGN distortion. The proposed analytical model is verified by ns3 software network simulator, whose test results are found to match the corresponding estimated values. This indicates that both spectral and energy efficiencies of small-cell networks are higher than in larger-cell networks, even more for heterogeneous two-tier networks.
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Paper Nr: 15
Title:

Impact of Physical Layer Impairments on C+L-band Metro Networks
Authors:

Filipa F. Gomes, Luís G. Cancela and João L. Rebola
Abstract: To ensure future data traffic capacities, multi-band transmission in optical networks is being proposed, by adding wavelength division multiplexing channels in the L-band to the existing C-band channels. In this work, we study the filterless drop and waste amplified and unamplified solutions used in metro networks with L-band tributary nodes. The cost and power consumption of these nodes is evaluated, as well as the impact of several physical layer impairments on the network performance. In amplified solutions, we show that L-band networks with 9 tributary nodes are feasible, being the optical signal-to-noise ratio achieved when considering amplifiers noise and fiber non-linear interference above 14 dB. In unamplified solutions, to fullfil the power budget, frequency reuse should be used between spans. We show that the in-band crosstalk caused by this frequency reuse leads to 1.5 dB power budget degradation, for a crosstalk level of -20 dB.
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Paper Nr: 17
Title:

MUFF: A Low-cost Motorized Positioner Developed by Additive Manufacturing to Obtain Multi-focus Images
Authors:

Gustavo Lelis da Silva, Jorge Stolfi and Helena G. Leitão
Abstract: Multifocal microscopy is an established technique to combine several reflected-light microscopy images of an object, each with a limited depth of focus, into a single image that shows the whole object in focus. Photometric stereo is an independent technique to recover the third dimension of an opaque object, given several images taken from the same viewpoint with different illumination conditions. We describe a low-cost motorized positioning device for the automatic acquisition of multiple reflected-light low-power microscope images of an object for combined multifocal and photometric stereo capture of millimeter-scale objects. The device automatically varies the microscope-to-object distance and the light direction, under control of an Arduino microcontroller. The device consists of a supporting frame, a microscope holder with motorized vertical displacement, an illumination stage with multiple light sources, and control electronics. The mechanical and structural parts are largely 3D-printed. The electronics is based on the Arduino microcontroller. The device is driven through an USB cable by a Python program that runs on a PC.
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Paper Nr: 21
Title:

Optimized Detection of Hypoglycemic Glucose Ranges in Human Serum by Raman Spectroscopy with 532 nm Laser Excitation
Authors:

Ata Golparvar, Assim Boukhayma, Christian Enz and Sandro Carrara
Abstract: Raman scattering-based biomedical detection has usually been proposed with near-infrared laser sources. However, a low-cost CMOS imager’s quantum efficiency is optimum around green wavelength, and their sensitivity substantially decreases in near-infrared wavelengths. Additionally, since Raman scattering intensity is proportional to λ-4, where λ is the laser wavelength, the increase of wavelength directly results in less sensitive measurement. These facts contribute to limiting the transfer of detection methodologies based on Raman spectroscopy to portable and low-cost point-of-care medical devices. Therefore, here we propose 532 nm green laser-induced Raman spectroscopy for low human serum glucose level detection. However, in 532 nm Raman spectroscopy of carotenoid containing biological systems, such as human serum, resonance Raman occurs, and total carotenoids resonance bands dominate the spectra. To demonstrate serum glucose detection on concentration levels typical in severe hypoglycemic ranges, this study optimizes laser focal depth, laser excitation duration, and laser power to extend the sensitivity by exploiting the glucose Raman shift peak at 1125 ± 7.5 cm–1. By applying experimentally tuned parameters, our findings suggest sensitive detection of serum glucose in the range of 0–10 mmol/l with 1.2 mmol/l theoretical limit of detection (LOD) by using spontaneous (non-enhanced) Raman spectroscopy.
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Paper Nr: 11
Title:

Quality Analysis and Colour Decoding of Printed Matters using a Portable 2D Chroma Meter
Authors:

Cheng-Ru Li, Chih-Chung Yang, Chun-Han Chou, Ming-Yen Lin and Yu-Hsuan Lin
Abstract: The paper presents an optical imaging system for the colour distribution measurement of objects. It has the advantages of portable, accuracy and high resolution. The lens barrel and the ring sunlight LEDs are designed to achieve regional darkroom, high illumination uniformity and high color rendering. After using a small color chart for calibration, the average color deviation (ΔE*ab) of the imaging system will be lower than 3. The uniformity of the printed papers could be successfully analysed and achieve color encryption application. This technology provides a useful solution for imaging and print technology that is very demanding on color correctness.
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Paper Nr: 18
Title:

Sensing Bandwidth Enlargement with Ten Orthogonal Codes in Quasi-distributed Acoustic Sensing System
Authors:

Ziwen Deng, Ruobing Xu, Yuyao Wang, Jialin Jiang and Zinan Wang
Abstract: In recent years, quasi-distributed acoustic sensing (QDAS) has attracted lots of attentions and shows great advantages in various fields such as structure health monitoring, intrusion sensing and so on. Sensing bandwidth is one of the essential indexes in QDAS, and there is a trade-off between sensing bandwidth and sensing distance. To break the limitation, the multiple-input multiple-output (MIMO) technology and ten orthogonal codes in the same frequency (OCSF) are utilized as an innovative technology to multiplex the sensing channel in a real-time long-distance QDAS system. In this paper, the sensing bandwidth of QDAS is enlarged to 5 kHz on 99.4 km sensing fiber, which is ten times of that in the conventional QDAS without channel multiplexing; a 4.9 kHz sinusoidal signal is retrieved in real time successfully, with 10 m spatial resolution and 43.8 pɛ/√Hz noise level.
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Area 3 - Photonics

Full Papers
Paper Nr: 7
Title:

Moving Gap Solitons in Semilinear Coupled Bragg Gratings with a Phase Mismatch
Authors:

Shuvashis Saha and Javid Atai
Abstract: We consider the existence and stability of the moving gap solitons in a semilinear coupler where one core has Kerr nonlinearity and the other is linear and both cores are equipped with a Bragg grating with a phase mismatch between them. We analyze the effect of the phase mismatch and the soliton velocity on the existence and stability of moving gap solitons. It is found that larger phase mismatch leads to the expansion of the stability region of the moving gap solitons.
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Paper Nr: 12
Title:

Solid-state Photoluminescent Quantum Dots for Explosive Detection
Authors:

Federica Mitri, Andrea De Iacovo, Serena De Santis, Carlo Giansante, Davide Spirito, Giovanni Sotgiu and Lorenzo Colace
Abstract: Quantum dots are an emerging class of photoluminescent nanomaterials with peculiar properties arising from their nanometric size that allows the occurrence of strong quantum confinement effect. In recent years, these zero-dimensional semiconductor nanoparticles have been attracting increasing attention as luminescent probe for optical sensing applications. However, to date, almost all quantum dots- based sensors reported in literature exploit fluorescence from solutions whereas the development of solid-state photoluminescent quantum dots still remains a challenge. In this paper, we demonstrate the feasibility of exploiting the solid-state photoluminescence of PbS quantum dots deposited on a silicon substrate for vapor explosive detection, a worrying priority for homeland security and counter-terrorism applications.
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Paper Nr: 19
Title:

Acousto-optic k-space Filtering of Optical Beams
Authors:

Konstantin B. Yushkov
Abstract: Acousto-optic tunable filters (AOTFs) can be used for spatial filtering of optical beams. A noncollinear AOTF has a tunable ring-shaped transfer function determined by geometry of the refractive index surface in a uniaxial crystal. Different axially symmetric transfer functions can be synthesized using multi-frequency ultrasonic signals. In the report, theory of AOTF-based spatial filtering of optical beams is summarized. Specific transfer function of the AOTF — bandpass spatial frequency filter — enables hyperspectal phase imaging in dark-field mode using incoherent illumination. Operation of a dynamic ring-shaped optical trap based on the noncollinear AOTF is demonstrated.
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Short Papers
Paper Nr: 13
Title:

Improvement of Thermal Resistance of Surface-emitting Quantum Cascade Laser using Structural Function and 3D Thermal Flow Simulation
Authors:

Shigeyuki Takagi, Hirotaka Tanimura, Tsutomu Kakuno, Rei Hashimoto, Kei Kaneko and Shinji Saito
Abstract: We have evaluated the thermal resistance of the surface-emitting QCL, which is expected to increase the output and improve the beam quality, based on the structure function and 3D heat flow resolution. From the structure function, the thermal resistance of the surface emitting QCL was divided into the mesa for laser excitation, the InP substrate, and the CuW mount, and the total thermal resistance of 8.0 K/W was obtained. The thermal resistance obtained by the 3D thermal analysis simulation was estimated to be 8.3 K/W, which was in good agreement with that obtained from the structure function. Furthermore, the effect of the diamond submount was evaluated and it was shown that the thermal resistance was reduced to 5.2 K/W. It is considered that the thermal resistance is reduced by the horizontal transfer of heat in the diamond submount.
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Paper Nr: 26
Title:

Silica Coated Plasmonic Nanobone-based Tags for Safe Bioimaging
Authors:

Aleksei N. Smirnov, Vasilisa O. Svinko, Aleksei S. Strelnikov, Alisa I. Shevchuk, Anna V. Volkova and Elena V. Solovyeva
Abstract: Fluorescence tomography is a hopeful medical imaging technique. However, this method has restrictions consisting in absorbance and scattering of optical signal by tissue. The present research is devoted to overcome these challenges utilising plasmonic nanoparticles. A new type of gold nanoparticles was synthesized, having a bone-like shape which provides the maximum of unimodal absorption band just in the middle of the biological tissues transparency range (600-800 nm). The nanobones were further modified with cyanine 5.5 and 7 fluorophores by electrostatic immobilization and coated by silica shell via two different techniques to instill biocompatibility. Resulting nanoparticles were characterised by dynamic light scattering, transmission electron microscopy, fluorescent and Raman spectroscopy. It is shown that a thickness of silica shell may be tuned precisely and that the nanoparticles may also be coated directly using mercaptopropyltrimethxysilane. The registered surface-enhanced Raman scattering and fluorescent signals depend on a position of cyanine dye in nanoparticle shell. Intensive fluorescent signal from the nanoparticles covered with silicon dioxide using mercaptopropyltrimethxysilane proved an incorporation of cyanines into shell during its growth.
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