Lidé

Ing. David Mareš, Ph.D.

Všechny publikace

Active Optic Glass for Broad-band Amplification by Erbium-Bismuth Activators

  • DOI: 10.1117/12.2664952
  • Odkaz: https://doi.org/10.1117/12.2664952
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Our work presents research of the optical Ge-Si glass composition doped with Er3+, Yb3+ ions and Bi optically active centers (BACs), which are useful for optically amplifiers for a double C- and U-band. The luminescence response in the 1500 – 1700 nm range was tested with various types of glass with different content of modifier and activators in the 1500 – 1700 nm range. The maxima of the luminescence intensity and the spectral full width were determined by modified reflex spectrum method measurement. The prepared Ge-Si glass doped with Er3+ ions and BACs exhibited strong and balanced emission in the 1520 – 1680 nm range after pumping at 1480 nm. The specific balanced optical differential gain of up to 0.2 dB/cm in the C-band and simultaneously 0.2 dB/cm in the U-band was measured. The measured results prove that the investigated germano-silicate glasses doped with Er3+ and Bi ions are promising for optical amplifiers working in the optical C- and U-bands.

Erbium-bismuth-doped germanium silicate active optic glass for broad-band optical amplification

  • DOI: 10.1016/j.optmat.2023.113621
  • Odkaz: https://doi.org/10.1016/j.optmat.2023.113621
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    This work deals with research and optimization of the optical Ge-Si glass composition doped with Er3+, Yb3+ ions and bismuth optically active centers (BACs), which are optically active for implementation in a double C- and U-band planar optical amplifier. The intention was to increase the range of amplified wavelengths in the NIR band up to 1650 nm. Various types of glass with different content of GeO2, SiO2 and Er2O3, Yb2O3 ions Bi2O3 were prepared and the luminescence response in the 1500-1700 nm range was tested. The maxima of the luminescence intensity in the optical bands and the spectral full width at half maximum (FWHM) were determined by modified reflex spectrum method measurement. The prepared Ge-Si glass doped with Er3+ ions and BACs exhibited strong and balanced emission in the 1520-1680 nm range after pumping at 1480 nm. The specific balanced differential gain of up to 0.2 dB/cm in the C-band and simultaneously 0.2 dB/cm in the U-band was measured. Our results proved that the luminescence of BACs depends on the presence of optical active Er3+ ions and germanium in matrix of glass, pumped by radiation 1480 nm and energy transfer from erbium to BACs have been newly observed in the Ge-Si glass. It has also been found that high content of germanium, comparable with silicon content is required for this transfer. The results show that the germano-silicate glass doped with Er3+ and Bi ions is a perspective material for the fabrication of broad-band amplifiers in the C- and U-bands.

Inorganic-organic hybrid polymer multimode optical channel waveguides

  • DOI: 10.1007/s00542-023-05567-x
  • Odkaz: https://doi.org/10.1007/s00542-023-05567-x
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    The paper reports on the fabrication and characterisation of the hybrid polymer multimode optical channel waveguides that have been used for core layers, namely OrmoClear (R) FX and OrmoCore. UV photopolymer was utilised for the cladding layers. The optical losses of the channel waveguides were measured by the cut-back method, and the lowest value for channel waveguides with the OrmoClear (R) FX core, specifically 0.22 dB/cm, was observed at 650 nm. The optical losses at 850 nm were 0.30 dB/cm and at 1310 nm, they were 0.47 dB/cm. OrmoCore channel waveguides had the lowest optical losses of 0.26 dB/cm at 850 nm, 0.32 dB/cm at 650 nm and 0.48 dB/cm at 1310 nm. The study has demonstrated that both hybrid polymers have suitable properties for the fabrication of optical waveguides for micro-opto-electro-mechanical systems and integrated optics applications for operating at 650 nm, 850 nm and 1300 nm.

Local detection of gaseous carbon dioxide using optical fibers and fiber tapers of single-cell dimensions

  • DOI: 10.1016/j.snb.2022.132887
  • Odkaz: https://doi.org/10.1016/j.snb.2022.132887
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    The CO2 amount in the air and its monitoring is widely recognized as an important issue at this time. We are facing excessive CO2 production and global warming affecting not only the environment but also life at the lowest level. A variety of strategies have been designed to reduce atmospheric CO2, but one promising method is based on the application of biologically engineered microorganisms to actively consume a high volume of CO2. The paper presents the design, development, and characterization of two types of sensors for the local detection of gaseous carbon dioxide on microscopic scale. The first one was designed as a fiber optic CO2 measuring cell and the second was based on a CO2 sensitive fiber taper tip. The sensors were based on the absorption of guided visible light in a sensitive polymer layer. The sensors were characterized in the range of 0%-10.6% of carbon dioxide concentration with full linearity. A sensitivity of 0.25 +/- 0.05 dB/% and a limit of detection of 7.1.10(-3)% have been determined for the sensing element. We have experimentally verified the operational reversibility of the CO2 sensing element over time. The time response of the sensor with the finally used sensitive layer of thickness of 600 nm was one second. Both sensors were designed for future application in biological research. Especially the second type of the sensor based on 3 mu m silica glass taper tip (diameter corresponding to single-cell proportions) is suitable for laboratory testing of microorganisms and cells that actively consume gaseous carbon dioxide.

Cu/Ag Nanoparticle-Based Surface-Enhanced Raman Scattering Substrates for Label-Free Bacterial Detection

  • DOI: 10.1021/acsanm.2c02571
  • Odkaz: https://doi.org/10.1021/acsanm.2c02571
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Surface-enhanced Raman spectroscopy (SERS) is a promising analytical technique for fast and accurate disease detection due to its attractive features. However, realizing label-free direct detection is still challenging as most probes have extremely low Raman cross sections and little affinity to SERS substrates. Disappointingly, SERS spectra of most bacteria and other biological samples look similar as the differences in their molecular compositions are subtle and not detectable. Hence, the fabrication of highly enhancing plasmonic nanoparticles with excellent uniformity is demanded. Moreover, as SERS substrates are not reusable, cost-effective and simplistic fabrication methods are critical. Here, we report a facile approach to synthesizing Ag nanoparticle array on Cu-foil in less than 3 min, using only Cu-foil, silver nitrate, and hydroquinone. We employed the idea of galvanic replacement in combination with a seed mediated particle-growth approach. The label-free bacterial detection has shown that our Cu/Ag nanoparticle substrate is superior to highly acclaimed Ag nanocubes. Creating strong second and third-generation SERS hot-spots through cooperative interaction of homo-(Ag-Ag) and heterogeneous (Ag-Cu) surfaces contributes mainly to the observed excellent enhancement. Interestingly, direct liquid bacteria sample analysis showed a 6-fold higher detection sensitivity than completely dried samples. We believe that our approach will offer remarkable advantages and change how SERS substrates are prepared and conducted in SERS-based bacterial detection.

Hybrid polymer-glass planar Bragg grating as a temperature and humidity sensor

  • DOI: 10.1007/s11082-022-04003-0
  • Odkaz: https://doi.org/10.1007/s11082-022-04003-0
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    This paper presents the design and construction of a new planar optical Polymer Waveguide Bragg grating (PWBG) temperature and humidity sensor realized by polymer-glass hybrid technology composition with a new layout concept. The Bragg grating of a sensor was made by a Direct Laser Writing (DLW) in Poly (methyl methacrylate) (PMMA) formed on a multimode waveguide realized in a glass substrate by Ag+ <-> Na+ ion exchange. The fabricated hybrid Bragg grating structure exhibited more than 10 dB of the attenuation dip, equivalent to higher than 90% diffraction efficiency. The fabricated hybrid PWBG sensor exhibited high temperature and humidity sensitivity in contrast to glass-based sensors of - 48.6 pm/degrees C and 54.16 pm center dot RH-1, respectively.

SERS OF ORGANIC ANALYTE ON THE FILTER PAPER WITH TiO2 ALD COATING AND AG NANOPARTICLES

  • Autoři: doc. RNDr. Jan Voves, CSc., Ing. David Mareš, Ph.D., Dadashov, R., Su, W.-N., Suwito, S., Beyene, A.B.
  • Publikace: NANOCON Conference Proceedings - International Conference on Nanomaterials. Ostrava: TANGER, 2022. p. 297-302. ISSN 2694-930X. ISBN 978-80-88365-09-9.
  • Rok: 2022
  • DOI: 10.37904/nanocon.2022.4618
  • Odkaz: https://doi.org/10.37904/nanocon.2022.4618
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Surface Enhanced Raman Spectroscopy (SERS) is an important method for characterizing different materials and chemical analytes at low concentrations. The Raman signal plasmonic amplification is strongly dependent on the surface nanostructure. The filter paper could be used as the substrate for the chemical analysis of organic materials. We investigated the influence of different TiO2 thicknesses deposited on the ashless filter paper surface on the signal efficiency. TiO2 is hydrophilic and biocompatible. High-surface area TiO2 on the filter paper will help create 3D heterostructure to collect more analyte molecules. We used Sentech SI 500 thermal Atomic Layer Deposition (ALD) System with 10, 20, and 50 growth cycles and the TTIP precursor. Surface structure was investigated by Atomic Force Microscopy (AFM). The silver (Ag) colloid solution was dropped on the filter paper before standard R6G biomarker solutions were deposited. The Raman signal measured by In Via Renishaw spectrometer was compared for the different samples. TiO2 ALD-20 cycle gave the highest enhancement factor (~2.3 X 105) compared to other ALD-coated samples. Interestingly, the TiO2 ALD coating generally results in an enhancement factor more than 20 times higher than the reference sample (namely filter paper without the ALD coating). SERS mapping results suggest the uniformity and reliability of SERS measurements across a large area (40 x 40 um2). The finding paves a new direction for preparing simple, flexible, and biocompatible SERS substrates, which could be readily applied in detecting various biomolecular or organic analytes in our coming works.

Smart Modulators Based on Electric Field-Triggering of Surface Plasmon-Polariton for Active Plasmonics

  • Autoři: Svanda, J., Kalachyova, Y., Ing. David Mareš, Ph.D., Siegel, J.
  • Publikace: Nanomaterials. 2022, 12(19), ISSN 2079-4991.
  • Rok: 2022
  • DOI: 10.3390/nano12193366
  • Odkaz: https://doi.org/10.3390/nano12193366
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Design and properties of a plasmonic modulator in situ tunable by electric field are presented. Our design comprises the creation of periodic surface pattern on the surface of an elastic polymer supported by a piezo-substrate by excimer laser irradiation and subsequent selective coverage by silver by tilted angle vacuum evaporation. The structure creation was confirmed by AFM and FIB-SEM techniques. An external electric field is used for fine control of the polymer pattern amplitude, which tends to decrease with increasing voltage. As a result, surface plasmon-polariton excitation is quenched, leading to the less pronounced structure of plasmon response. This quenching was checked using UV-Vis spectroscopy and SERS measurements, and confirmed by numerical simulation. All methods prove the proposed functionality of the structures enabling the creation smart plasmonic materials for a very broad range of advanced optical applications.

Er3+/Yb3+ doped active optic Y splitter realized by diffusion waveguides with Ag+-Na+ ion exchange

  • DOI: 10.1007/s11082-021-03035-2
  • Odkaz: https://doi.org/10.1007/s11082-021-03035-2
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    We reported on the active channel waveguides, formed in novel types of silicate glasses, doped with rare-earth elements, and Zn were investigated. The silicate glass GZ4 with Er3+ and Yb3+ content was studied, and the best doping ratio was estimated about luminescent properties. The composition of the glass samples (GZ4) with the content of 0.25 mol.% Er2O3 and 5.0 mol.% Yb2O3 and 12.0 mol.% resp. 18.0 mol.% ZnO was optimized. This glass was evaluated as the most suitable material for integrated amplifiers in the 1 530-1 565 nm telecommunication band. Other samples were prepared with active channel waveguides and active planar optical power splitter Y with a splitting ratio of 1x2 by two-step ion-exchange Na+<-> Ag+. Diffusion profiles of the created samples were analyzed by the EMA microscope and compared with the near mode-field distribution measurement results. Afterward, the amplification properties of the designed structures were studied, and the differential gain from 1.2 to 1.6 dB (0.48 to 0.64 dB/cm) was achieved by pumping power 200 mW at 980 nm.

Precise cancer detection via the combination of functionalized SERS surfaces and convolutional neural network with independent inputs

  • Autoři: Erzina, M., Trelin, A., Guselnikova, O., Dvořánková, B., Strnadová, K., Perminova, A., Ulbrich, P., Ing. David Mareš, Ph.D., doc. Ing. Vítězslav Jeřábek, CSc., Elashnikov, R., Svorčík, V., Lyutakov, O.
  • Publikace: Sensors and Actuators B: Chemical. 2020, 308 ISSN 0925-4005.
  • Rok: 2020
  • DOI: 10.1016/j.snb.2020.127660
  • Odkaz: https://doi.org/10.1016/j.snb.2020.127660
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Combining the advanced approaches of surface functionalization and chemistry, plasmonics, surface enhanced Raman spectroscopy (SERS), and machine learning, we propose the advanced route for express and precise recognition of normal and cancer cells. Our interdisciplinary approach uses plasmonic coupling between the specific nanoparticles and underlying periodical plasmonic surface and achieves high SERS enhancement factor. The surface of gold multibranched nanoparticles (AuMs) was functionalized with different chemical groups to achieve partially selective entrapping of biomolecules from cells cultivation media and generate information-rich inputs for machine learning methods and SERS-based cells recognition. Evaluation of convolutional neural networks (CNN) training results, performed with ad hoc feature selection method, suggests that the grafted functional groups provide specificity to proteins, nucleic acids and lipids, responsible for cancer line identification. The dataset of SERS control spectra of normal and cancer cell’s metabolites were classified by the trained CNN and perfectly distinguished with 100 % prediction accuracy.

Longtime stability of silver-based SERS substrate in the environment and (bio)environment with variable temperature and humidity

  • DOI: 10.1016/j.sna.2018.11.037
  • Odkaz: https://doi.org/10.1016/j.sna.2018.11.037
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    The increased involving of SERS in the analytical and bioanalytical field makes this technique commercially available. However, the growing range of commercially available SERS substrates opens the question regarding the stability of SERs substrates during their storage, transportation, and utilization. In this paper, we present systematical study of the stability of SERS enhanced response of silver grating under various physical and chemical load. The silver coated periodical gratings were used as SERS substrates since they provide excellent enhancement of Raman signal, perfect reproducibility and reliability of SERS signal, achieved at the macroscale. The substrate load procedures include the temperature, humidity tests, and their combination. Since the utilization of SERS substrates often involves their interaction with various (bio)environments, the effects of physiological media were studied too. In all cases, the effects of the loads were determined from the changes of SERS effectivity and reproducibility.

Unprecedented Plasmon-Induced Nitroxide-Mediated Polymerization (PI-NMP): a Method for Preparation of Functional Surfaces

  • DOI: 10.1039/c9ta01630a
  • Odkaz: https://doi.org/10.1039/c9ta01630a
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    A plasmon as a stimulus opens up new opportunities for selective and regulated “from-surface” polymerization and functionalization of surfaces. Here, the first example of plasmon-assisted nitroxide-mediated polymerization (NMP) of stimuli-responsive block copolymers poly(N-isopropylacrylamide)-co-4‐vinylboronic acid is reported. The growth of polymer film at room temperature was achieved via plasmon-induced homolysis of alkoxyamines covalently attached to the surface of plasmon-active gold gratings at room temperature. Control of temperature, finite-difference time-domain method simulation of plasmon intensity distribution shift during polymerization, electron paramagnetic resonance experiments, and other assays provide strong support for the plasmon-initiated mechanism of NMP. We demonstrated not only the control of resulting polymer thickness but also the preparation of a SERS chip for detection of glycoproteins as a powerful example of plasmon-assisted NMP potential.

Laser patterning of transparent polymers assisted by plasmon excitation

  • DOI: 10.1039/c8sm00418h
  • Odkaz: https://doi.org/10.1039/c8sm00418h
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Plasmon-assisted lithography of thin transparent polymer films, based on polymer mass-redistribution under plasmon excitation is presented. The plasmon-supported structure was prepared by the thermal annealing of thin Ag films sputtered on glass or glass/graphene substrates. Thin films of polymethylmethacrylate, polystyrene and polylactic acid were then spin-coated on the created plasmon-supported sutructures. Subsequent laser beam writing, at the wavelength corresponding to the position of plasmon absorption, leads to mass redistribution and patterning of thin polymer films. The prepared structures were characterized by UV-Vis, confocal and AFM microscopy. The shape of prepared structures was found to be strongly dependent on a substrate type. The mechanism leading to polymer patterning was examined and attributed to the plasmon-heating. The proposed method makes possible to create different patterns in polymer films without the need for wet technological stages, powerful light sources or change in polymer optical properties.

SERS sensor based on functionalized gold grating as a platform for the signal improvement on a portable Raman spectrometer

  • Autoři: Guselnikova, O., Kalachyova, Y., Ing. David Mareš, Ph.D., Postnikov, V., Svorčík, V., Lyutakov, O.
  • Publikace: 29th Conference and Exhibition on OPTICAL COMMUNICATIONS 2018. Praha: Zeithamlová Milena Ing. - Agentura Action M, 2018. ISBN 978-80-86742-50-2.
  • Rok: 2018
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    We proposed a SERS-based universal sensor system, consisting of the highly-ordered gold grating, which enables to detect analytes on a molecular level and provide high reproducibility of response and a covalently grafted layer of organic functional groups (OFGs). OFGs serve as a capturing agent, enhancing the affinity to the analyte, what facilitates preconcentration of the analyte on the sensor surface and provide excellent selectivity. By proposed concept SERS sensor system can be functionalized by various ligands- for the rapid determination of metal ions, azo-dyes, cholesterol markers, DNA complementarity, trapping of pesticides and other contaminants, detection of specific markers of cancer cells, free radicals, enantiomeric excess in the validation of drugs. Suggested functionalized gold gratings demonstrate principal advantages for efficient SERS detection: expressivity, sensitivity, selectivity, pretreatment free procedure, and reproducibility.

Design and optimization of the silver nanograting structure utilizing surface plasmon-polariton for increase of SERS sensor response

  • DOI: 10.1117/12.2291467
  • Odkaz: https://doi.org/10.1117/12.2291467
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    This paper reports on the design of the surface enhanced Raman spectroscopy (SERS) structures that were optimized through computation and simulation to obtain the best enhancement of the surface plasmon-polariton (SPP) response on these structures. The structure of the silver nano-grating was designed, fabricated, optimized and measured. The enhancement factor and the increase in the absorption capabilities associated with SPP were evaluated. The rigorous coupled wave analysis (RCWA) and finite-difference time-domain (FDTD) computational/simulation methods were utilized. The comparison between the computation simulation outputs and the measured outputs of the fabricated samples was performed.

Sandwiched gold/PNIPAm/gold microstructures for smart plasmonics application: towards the high detection limit and Raman quantitative measurements

  • Autoři: Elashnikov, R., Ing. David Mareš, Ph.D., Podzimek, T., Svorcik, V., Lyutakov, O.
  • Publikace: The Analyst. 2017, 142(16), 2974-2981. ISSN 0003-2654.
  • Rok: 2017
  • DOI: 10.1039/c7an00419b
  • Odkaz: https://doi.org/10.1039/c7an00419b
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    A smart plasmonic sensor, comprising the layer of stimuli-responsive polymer sandwiched between two gold layers, is reported. As a stimuli-responsive material, the monolayer of poly(N-isopropylacrylamide) (PNIPAm) crosslinked globules is used. A quasi-periodic structure of the top gold layer facilitates an efficient excitation and serves as a support of plasmon excitation and propagation. The intermediate layer of PNIPAm efficiently entraps targeted molecules from solutions. The sensor structure was optimized for an efficient light focusing in the “active” PNIPAm layer. The optimization was based on the time-resolved finite-element simulations, which take into account the thickness of gold layers, size of PNIPAm globules and Raman excitation wavelength (780 nm). The prepared structures were characterized using SEM, AFM, UV-Vis refractometry and goniometry. Additional AFM scans were performed in the water at two temperatures corresponding to the collapsed and swollen PNIPAm state. The Raman measurements demonstrate a high detection limit and perfect reproducibility of Raman scattering signal for the prepared sensor. In addition, the use of created SERS structures for the detection of relevant in the medical, biological and safety fields was demonstrated.

Ultrasensitive and reproducible SERS platform of coupled Ag grating with multibranched Au nanoparticles

  • DOI: 10.1039/c7cp01828b
  • Odkaz: https://doi.org/10.1039/c7cp01828b
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Surface-enhanced Raman scattering (SERS) spectroscopy is an extremely sensitive analytical technique that is capable of identifying the vibration signatures of target molecules up to single-molecule sensitivity. In this work, the ultrahigh sensitivity of SERS has been achieved through the immobilization of sharp-edges specific nanoparticles - so-called gold multibranched NPs (AuMs) on the silver grating surface through the biphenyl dithiol. This approach allows combining the extremely high SERS enhancement factor (better than that in the case of AuMs immobilized on the flat Ag film) with perfect reproducibility of Raman signals. The grating was created on the polymer substrate using the excimer laser modification and further metal deposition and has an "active'' area 5 x 10 mm(2), enabling the macroscale SERS substrate preparation. The wet-chemistry synthesized AuMs were then immobilized on the grating surface and the produced structure allows SERS measurements with a portable Raman spectrophotometer. The prepared structures were checked using the AFM, UV-Vis, and Raman spectroscopy techniques.

Polymer waveguide Bragg gratings made by laser patterning technique

  • DOI: 10.1007/s11082-016-0438-9
  • Odkaz: https://doi.org/10.1007/s11082-016-0438-9
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Planar waveguide gratings are very useful components for planar optical structures in which they function as wavelength optical filters, demultiplexers or sensors. The Bragg gratings formed on planar optical waveguides in multimode propagation regime show multiple reflections, which can lead to enlargement of the envelope of the dip transmission spectral characteristic. This paper reports on the design and measurement of the two types multimode planar optical waveguides with diffraction Bragg grating (PWBG) made on the core or cladding layer of the structure. In the first monostructural design, PWBG was made from an optical epoxy polymer SU-8. The second hybrid PWBG design was based on ion exchange Ag+ ↔ Na+ glass waveguide. A grating was made in polymethylmethacrylate cladding layer covering the waveguide. The third-order polymer PWBGs with grating constant Λq−3 = 1.35 µm or Λq−3 = 1.2 µm were prepared by new laser-thermal patterning technique based on Marangoni effect. Based on experimental and theoretical results, the topological parameters of the structures were optimized to obtain maximum diffraction efficiency of the polymer PWBG. The beam propagation method and the rigorous coupled-wave analysis were used in theoretical modelling, simulation and evaluation of designed PWBG dimension parameters. The Bragg wavelengths transmission dips were measured in NIR optical band at λ = 1187 nm or λ = 1430 nm, respectively. The spectral transmission attenuation dips were 10 and 15 dB corresponding to 90 and 97 % diffraction efficiency of polymer PWBGs. The advantage of multimode PWBGs and its applications are discussed.

The Effect of Silver Grating and Nanoparticles Grafting for LSP-SPP Coupling and SERS Response Intensification

  • DOI: 10.1021/acs.jpcc.6b01587
  • Odkaz: https://doi.org/10.1021/acs.jpcc.6b01587
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    The systematic study of structures with gold and silver nanoparticles (MeNPs) of various shape and dielectric function immobilized onto the silver grating is performed. The structures may serve as double resonance SERS (Surface-enhanced Raman spectroscopy) systems with the coupling between surface plasmon polaritons (SPPs) supported by the silver grating and localized surface plasmons (LSPs) excited on the grafted metals nanoparticles (MeNPs). The silver grating supports SPP excitation under the 785 nm wavelength illumination. Spherical silver and gold nanoparticles, triangular silver nanoprisms and gold nanorods are prepared and used with the aim to gradually cover the LSP excitation in 400-850 nm wavelength range. MeNPs are grafted through the 4,4'-biphenyldithiol (BFDT) linkers. Rhodamine 6G (R6G) molecules are added onto SERS substrates and located above and between the MeNPs. Several wavelengths (470, 532, and 785 nm) are applied to probe the SERS response. Depending on the nanoparticles type and excitation wavelength the significant SERS signal is produced by R6G or BFDT molecules. The properties of the prepared structures are simulated using Finite-difference time-domain method (FDTD). Measured and simulated SERS data are in reasonable agreement, the measured values being lower than those calculated.

Thulium-doped fibre broadband source for spectral region near 2 micrometers

  • Autoři: Písařík, M., Peterka, P, Aubrecht, J, Cajzl, J, Benda, A, Ing. David Mareš, Ph.D., Todorov, F, Podrazský, O, Honzátko, P, Kašík, I
  • Publikace: Opto-Electronics Review. 2016, 24(4), 223-231. ISSN 1230-3402.
  • Rok: 2016
  • DOI: 10.1515/oere-2016-0022
  • Odkaz: https://doi.org/10.1515/oere-2016-0022
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    We demonstrated two methods of increasing the bandwidth of a broadband light source based on amplified spontaneous emission in thulium-doped fibres. Firstly, we have shown by means of a comprehensive numerical model that the full-width at half maximum of the thulium-doped fibre based broadband source can be more than doubled by using specially tailored spectral filter placed in front of the mirror in a double-pass configuration of the amplified spontaneous emission source. The broadening can be achieved with only a small expense of the output power. Secondly, we report results of the experimental thulium-doped fibre broadband source, including fibre characteristics and performance of the thulium-doped fibre in a ring laser setup. The spectrum broadening was achieved by balancing the backward amplified spontaneous emission with back-reflected forward emission.

Design, simulation and optimization of silver nano-grating for optimal SERS response

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    In the paper are presented results of the design, simulation and optimization of a planar structure to surface enhance Raman spectroscopy (SERS) based on surface plasmon-polariton (SPP) effect used in a surface silver layer deposited on a SU-8 nano-grating. The behavior of the Ag-SU8 nano-grating and consequent SPP phenomenon was studied and simulated by solution of Maxwell's equations in periodic dielectric structures - Rigorous Coupled Wave Analysis (RCWA) algorithm enhanced by Modal Transmission Line. The convergence and simulation studies were performed for optimization of SPP structure parameters. It was found by simulation that the narrow range of grating periodicity and metal layer thickness exist, where SPPs effect can be most efficiently excited. Results and optimization of designed structure were used for fabrication of reproducible and effective SPP based SERS sensor.

Mobile Devices Displays Capabilities for the Visible Light Communication

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Visible light communication (VLC) is expected to be an important part of the next generation networks. It offers a secondary usage of visible light for an information transmission. It determines many current types of mobile devices to use for VLC without any hardware change. An important part of all communication devices is a transmitter. This paper deals with available display technology used as an optical information transmitter for the purpose of VLC. The different types of liquid crystal displays (LCD) and an organic light emitting diode (OLED) display have been compared. The important characteristics for VLC implementation such as time response, view angle, output power etc. have been compared. Moreover, the display behavior can be also influenced by display drivers. This paper also covers limitations and possibilities of driving displays using hardware implemented drivers, frame buffers or software application running on operation system as a display driver. To sum up the results, the comparison of all characteristics has been done.

Surface Plasmon Polaritons on Silver Gratings for Optimal SERS Response

  • Autoři: Kalachyova, Y., Ing. David Mareš, Ph.D., Lyutakov, O., Kostejn, M., Lapcak, L., Švorčík, V.
  • Publikace: The Journal of Physical Chemistry C. 2015, 119(17), 9506-9512. ISSN 1932-7447.
  • Rok: 2015
  • DOI: 10.1021/acs.jpcc.5b01793
  • Odkaz: https://doi.org/10.1021/acs.jpcc.5b01793
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    One of the most important obstacles for the application of surface enhanced Raman spectroscopy (SERS) is the poor reproducibility of SERS active substrates: SERS intensity can be varied from one substrate to another and moreover along the one substrate surface. Reproducible SERS substrate can be prepared through introduction of highly ordered metal array, where light focusing is achieved through excitation of surface plasmon-polaritons (SPPs). In this work, excimer laser patterning of poly(methyl methacrylate) followed by silver evaporation is proposed as an effective way for the creation of reproducible and effective surface plasmon-polaritons (SPP)-based SERS substrate. Detailed theoretical and experimental studies were performed to optimize structure parameter for effective SPP excitation. It was found that the narrow range of grating periodicity and metal thickness exist, where SPPs can be most efficiently excited. Despite the fact that SERS response was almost always achieved, the enhancement factor was found to vary more with the effectivity of SPP excitation. When the real structure parameters were set to optimal for SPP excitation, a SERS enhancement factor was achieved up to four times.

Bi-directional triplexer with butterfly MMI coupler using SU-8 polymer waveguides

  • DOI: 10.1117/12.2073239
  • Odkaz: https://doi.org/10.1117/12.2073239
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    We report about a design of a bi-directional planar optical multiplex/demultiplex filter (triplexer) for the optical part of planar hybrid WDM bi-directional transceiver in fiber-to-the-home (FTTH) PON applications. The triplex lightwave circuit is based on the Epoxy Novolak Resin SU-8 waveguides on the silica-on-silicon substrate with Polymethylmethacrylate cladding layer. The triplexer is comprised of a linear butterfly concept of multimode interference (MMI) coupler separating downstream optical signals of 1490 nm and 1550 nm. For the upstream channel of 1310 nm, an additional directional coupler (DC) is used to add optical signal of 1310 nm propagating in opposite direction. The optical triplexer was designed and optimized using beam propagation method. The insertion losses, crosstalk attenuation, and extinction ratio for all three inputs/outputs were investigated. The intended triplexer was designed using the parameters of the separated DC and MMI filter to approximate the idealized direct connection of both devices.

Design and Simulation of Polymer-based Waveguide Periodic Structures

  • Autoři: Ing. David Mareš, Ph.D.,
  • Publikace: POSTER 2014 - 18th International Student Conference on Electrical Engineering. Prague: Czech Technical University, 2014. ISBN 978-80-01-05499-4.
  • Rok: 2014
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    We report about the design and modelling of a planar optical waveguide diffraction Bragg grating made in an optical polymer.

Micro-optical insertion system for WDM transceiver

  • DOI: 10.1117/12.2073485
  • Odkaz: https://doi.org/10.1117/12.2073485
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    The paper deals with the design of an micro-optical part of a WDM transceiver based on the circle volume holographic grating triplexer (VHGT) topology. The work is focused on detail description of the bidirectional micro-optical insertion system, especially on the coupling in the transmission direction of the WDM transceiver optical part. This micro-optical wavelength distribution system is imagine transmission system consisted of collimating cylindrical lenses set in the circle topology with the VHGT filter placed in the middle of the circle. The topology is described by ray matrices equations, calculated using analytic and numeric methods and optically measured. Considering simulation and measurement results of micro-optical insertion system the influence of these characteristics on ray path attenuation, diffraction efficiency and transceiver performance is estimated. The paper also discusses limits and conditions of the laser asymmetrical beam focus into the input/output optical fiber.

The design of polymer planar optical triplexer with butterfly MMI filter and asymmetrical directional coupler

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Paper report about the 3D design of a planar MMI (multi-mode interference) butterfly filter for wavelengths 1490 and 1550 nm using epoxypolymer SU-8 2000 on the Si/SiO2 substrate. In the second part of this paper we discuss the parameters of a planar triplex filter consisting of the butterfly MMI filter and asymmetrical directional coupler (DC).

Design and Technology of Planar Polymer Waveguide Bragg Grating

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    We report about design, technology and fabrication of a planar optical polymer waveguide with Bragg grating. There were designed and realized two topological and technological variants of an optical waveguide grating. Polymer materials, namely poly(methyl methacrylate) (PMMA) and Epoxy-Novolak-Resin SU-8 (ENR) were chosen as basic materials of a planar lightwave grating circuit. A thin corrugated layer of the polymer is in the first case deposited on a glass substrate with an optical diffused single mode channel waveguide made by ion exchange. Bragg grating is realized here as the "cladding" layer of the diffused waveguide. In the second case is a corrugated ridge single mode waveguide made on SiO 2 /Si or borosilicate glass substrate.

The design of polymer planar optical triplexer with MMI filter and directional coupler

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Optical bidirectional WDM transceiver is a key component of the Passive Optical Network of the Fiber to the Home topology. Essential parts of such transceivers are filters that combine multiplexing and demultiplexing function of optical signal (triplexing filters). In this paper we report about a design of a new planar optical multi-wavelength selective system triplexing filter, which combines a multimode interference filter with directional coupler based on the epoxy polymer SU-8 on Si/SiO2 substrate. The optical triplexing filter was designed using the Beam Propagation Method. The aim of this project was to optimize the triplexing filter optical parameters and to minimize the planar optical wavelength selective system dimensions. The multimode interference filter was used for separation of downstream optical signal in designed optoelectronic integrated WDM transceiver. The directional coupler was used for add of upstream optical signal.

Waveguide Bragg Grating Filters Made from Optical Polymers

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    We report about the planar optical waveguide with a diffraction Bragg grating made in an optical polymer, which exhibits filter function useable for Passive Optical Network Fiber to the Home (PON FTTH) and sensor components. There were designed two topological and technological variants of an optical waveguide grating structures. The distribution of optical field and topological constants of waveguide grating was calculated and simulated by RSoft’s BeamPROP and GratingMode programs. The influence of topological parameters of waveguide grating filters like grating groove depth, waveguide layer thickness, length of the grating, etc. on key characteristic properties of the diffraction grating filter including diffraction efficiency, the central reflected wavelength, the bandwidth at 50% of the maximum transmission for guided modes and insertion losses were mainly investigated. Subsequently, structural parameters were optimized with respect to used fabrication methods.

Waveguide periodic structures from optical polymers usable as filter or sensor of temperature

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    The paper deals with the design, implementation, diagnostics, technological and topological optimization of planar waveguide structures with Bragg gratings, filtering and demultiplexing signals in passive optical information networks and sensor applications.

Design and Properties of Planar Polymer Waveguide Bragg Grating Filter

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    We report about the planar optical waveguide filter using a diffraction Bragg grating made in polymer, that shows filter function useable for PON FTTH components. There were designed two topological and technological variants of an optical waveguide grating filters. The first type of the optical waveguide grating filter was realized as a laser-heat shaped layer of PMMA (polymethylmethacrylate) on a glass substrate with an optical ion exchange waveguide. The second type was realized by laser-heat shaping of a SU-8 (epoxypolymer) ridge waveguide on SiO2/Si substrate. The distribution of optical field and topological constants of waveguide grating filters was calculated and simulated by RSoft's BMP and Grating Mode programs. Influence of topological parameters of waveguide grating filters like grating groove depth, waveguide layer thickness, length of the grating, etc. on key characteristic properties of the diffraction grating filter including diffraction efficiency, central reflected wavelength, the bandwidth at 50% of the maximum transmission (FWHM) for guided modes and insertion losses were mainly investigated. The waveguide filters were realized as relief Bragg gratings with roughly sinusoidal cross section of the layer that had influence at a guided optical mode. A Grating's period was chosen to satisfied higher order Bragg's phase condition due to technological limitations of the laser-heat manufacturing process. The grating constant can be continuously varied, which is a major asset for optimization process of Bragg's gratings with space modulated profile. Main properties of the optimized prototypes were then measured and evaluated.

MICROOPTICAL COLLIMATION SYSTEM FOR WDM RECEIVER WITH A BRAGG VOLUME GRATING

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    We report about design and measurement of wavelength division multiplexing (WDM) microoptical collimation system for WDM receiver module (WDM-Receiver). The collimation system is represented by ray matrix model and the focal distances obtained in the matrix are verified experimentally. The optic focal system: collimation lens- PIN photodiode (PIN-PD) is characterized to found the dependence between the diameter of the collimated beam and the covered active area in the PIN PD. The optical micromodule uses a microoptics hybrid integration technology with collimation lenses and a volume holographic Bragg grating triplex filter (VHG triplexer) for wavelength multiplex/ demultiplex.

Optical System using VHGT Filter for Wavelength Division Multiplexed (WDM) Hybrid Optoelectronic Receiver

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    This paper is about the design of three micro modules in a new circle topology and measurement of the optical micro module which uses a micro optics hybrid integration technology with collimation lenses and a volume holographic Bragg grating triplexer (VHGT) filter for wavelength multiplexing/de-multiplexing. The collimation system is represented by a ray matrix model and the focal distances obtained in the matrix are verified experimentally. The optic focal system: "collimation lens- PIN photodiode (PD)" is characterized to be found in the relationship between the diameter of the beam collimated and the active area covered in the PIN PD. The optical micro module with a VHGT filter and two optoelectronic receiver micro modules are for receiving download information (internet and digital TV signals).

Sistema Colimado Microoptico para receptores Wdm con filtro de Bragg

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Se presenta el diseño y mediciones de un receptor multiplexor por división de longitud de onda (MDL) en la tecnología de las microondas son su haz de luz colimado. El sistema de colimación es representado matemáticamente por un siste- ma de matrices mediante el cual se determina el punto focal el cual es verificado experimentalmente. El módulo óptico usa la tecnología micro-óptica híbrida integrada con lentes colimados y filtro de Bragg para multiplexar y demultiplexar los rayos de luz.

Microoptical and Microwave Design and Construction of a Micromodules for WDM Receiver

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    The paper presents design a novel topology and technology solution of IC microoptical hybrid integrated WDM receiver, composed of the optical and optoelectronic micromodules. The optical micromodule use volume holographic grating triplexer (VHGT) as unique optical multiwavlength demultiplexing element in WDM microsystem, The downstream microoptical imagine system was verified by construction and measurement of the microoptical hybrid integrated WDM receiver. Very low insertion optical losses and optical crosstalk of VHGT element imply the high sensitivity and the transmit distance of optical SM fiber. Further work was concentrated on design and construction of WDM transceiver realized by planar lightwave circuit hybrid integration technology. The optical part will be solved by polymer or glass interference filter or microoptical resonators.

Microoptical Collimation System for WDM Receiver with a Bragg Volume Grating

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    We report about design and measurement of wavelength division multiplexing (WDM) microoptical collimation system for WDM receiver module (WDM- Receiver). The collimation system is represented by ray matrix model and the focal distances obtained in the matrix are verified experimentally. The optic focal system: collimation lens- PIN photodiode (PIN-PD) is characterized to found the dependence between the diameter of the collimated beam and the covered active area in the PIN PD. The optical micromodule uses a microoptics hybrid integration technology with collimation lenses and a volume holographic Bragg grating triplex filter (VHGT) for wavelength multiplexing/ demultiplexing.

The Microoptical and Microwave Design and Construction of a WDM Receiver with Bragg Volume Grating Using Hybrid Integration Technology

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    We report about microoptical and microwave design and construction of WDM receiver module useable for the passive optical network (PON) of a fiber to the home (FTTH) topology. The WDM receiver uses a microoptics hybrid integration technology with volume holographic Bragg grating triplex filter (VHGT) and a collimation lenses for wavelength demultiplexing. A VHGT filters are ideal optical beam distribution element having high diffraction efficiency wavelength and very low insertion loses and optical crosstalk. The optical imaging system was design in the paraxial approximation by ray-transfer matrix. The optical WDM receiver was constructed using system of a three micromodules in the new circle topology, the optical micromodule and two microwave optoelectronics receiver micromodules (OE receivers). WDM receiver use radiation 1490 nm for internet and 1550 nm for digital TV signals download information.

WDM hybrid microoptical transceiver with bragg volume grating

  • DOI: 10.1117/12.911293
  • Odkaz: https://doi.org/10.1117/12.911293
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    The paper presents the design, simulation and construction results of the wavelength division multiplex bidirectional transceiver module (WDM transceiver) for the passive optical network (PON) of a fiber to the home (FTTH) topology network. WDM transceiver uses a microoptical hybrid integration technology with volume holographic Bragg grating triplex filter -VHGT and a collimation lenses imagine system for wavelength multiplexing/ demultiplexing. This transmission type VHGT filter has high diffraction angle, very low insertion loses and optical crosstalk, which guide to very good technical parameters of transceiver module. WDM transceiver has been constructed using system of a four micromodules in the new circle topology.

Za stránku zodpovídá: Ing. Mgr. Radovan Suk