8 research outputs found
Lossy mode resonance in photonic integrated circuits
No full textThe authors would like to acknowledge the Institute of Solid State Physics, University of Latvia. This research was supported by the European Regional Development Fund project 1.1.1.1/20/A/045 and the European Union's Horizon 2020 Framework Program H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.In recent years, the promising phenomenon known as lossy mode resonance (LMR) has garnered significant attention in sensing applications. While existing literature in the field of LMR focuses on optical fiber systems and planar waveguides due to their simplicity, there is an absence of research on systems based on photonic integrated circuits (PICs). This article aims to demonstrate, for the first time, the generation of LMR in PICs with sensitivity and a figure of merit (FOM) comparable to that of optical fibers and planar waveguides. Additionally, the article offers a comparison of various polymer materials such as OrmoClear, OrmoCore and SU-8 for integrated waveguides fabrication. To summarize, the main novelty of the article is the demonstration of the LMR phenomenon in integrated chips and the comparison of different polymers commonly used in photonics to fabricate these chips. Moreover, the authors present a novel fabrication workflow for thick polymer waveguides. Finally, the study compares the experimental results obtained with simulations conducted using the finite element method (FEM) in COMSOL Multiphysics environment. © 2024 --//-- This is an open-access article Edvins Letko, Arturs Bundulis, Edgars Vanags, Gatis Mozolevskis,
Lossy mode resonance in photonic integrated circuits, Optics and Lasers in Engineering, Volume 181, 2024, 108387, ISSN 0143-8166, https://doi.org/10.1016/j.optlaseng.2024.108387 published under the CC BY licence.European Regional Development Fund 1.1.1.1/20/A/045; European Union's Horizon 2020 Framework Program H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 739508, project CAMART2
Tunable Filtering via Lossy Mode Resonance in Integrated Photonics
No full textThis study explores an integrated tunable filter based on lossy mode resonance (LMR) in TiOx thin films, modeled in COMSOL Multiphysics using the Wave Optics and Semiconductor modules. By exploiting the electro-optic (EO) modulation of free carrier concentration in TiOx, the LMR wavelength can be actively tuned under an applied electric field. The results demonstrate a tuning efficiency of 4.0 nm/V, which surpasses many reported EO tunable filters. Optimization studies reveal that thinner ITO electrodes and TiOx layers enhance tuning efficiency, while the initial bulk free carrier concentration has limited influence due to the compensating effect of the Debye length. These findings extend the applicability of LMR beyond sensing, highlighting its potential for active photonic components in integrated optics
Theoretical Development of Polymer-Based Integrated Lossy-Mode Resonance Sensor for Photonic Integrated Circuits
No full textA promising phenomenon such as lossy-mode resonance (LMR) is of great interest in sensor applications. Until now, this phenomenon has been shown only in fibers or planar waveguides; however, given the rapid development of such an important technological area as photonic integrated circuits (PICs), it is important to transfer LMR technology specifically to PICs. In this article, we propose the theoretical development of an integrated polymer-based LMR sensor that will also contribute to the development of hybrid organic–inorganic PICs. This work theoretically shows that LMR can be achieved using polymer SU-8 waveguides on a glass substrate, on top of which TiO2 is deposited. In addition, the paper shows that multiple resonances can be achieved in the developed integrated sensor. The highest sensor sensitivity (about 1400 nm/RIU) was achieved with 40 nm of TiO2. The effect of the waveguide and coating geometries, as well as the polarizations of propagating modes, is studied in this paper
Birzgalis 5
No full textEdmonton-based Latvian Double Quartet circa 1955; back row left to right: Mr. Tigeris, Harry Skrastins, Albert Licis, Edvins Vitols, Harry Tarksis, unknown, Jadvins Antonovics, unknown, unknown.
front row left to right: unknown, Reverend Caune, Lidija Bagatais nee Tilts, Janis Muzis, Irma Lesins, Juris Toms, Mrs. Tom
Birzgalis05
No full textEdmonton-based Latvian Double Quartet circa 1955; back row left to right: Mr. Tigeris, Harry Skrastins, Albert Licis, Edvins Vitols, Harry Tarksis, unknown, Jadvins Antonovics, unknown, unknown.
front row left to right: unknown, Reverend Caune, Lidija Bagatais nee Tilts, Janis Muzis, Irma Lesins, Juris Toms, Mrs. Tom
Photoinduced Anisotropy of IWK-2D Azobenzene Molecular Glassy Films
No full textWe have experimentally studied photoinduced anisotropy (PA) of holographic gratings in IWK-2D [precise chemical notation: 2-(3-(4-((4-(bis (2-(trityloxy) ethyl) amino) phenyl) diazenyl) styryl)-5,5-dimethylcyclohex-2-enylidene) malononitrile] azobenzene molecular glassy films in transmission and reflection modes using a special simultaneous holographic recording and readout setups which enabled measurements of PA time evolution. PA manifested itself by diffraction efficiency difference with linear s- and p-polarizations. Three different types of polarization holographic gratings were recorded and studied using p-p, L-L and L-R polarized beams creating different recording interference patterns. Atomic force microscope (AFM) was used to study the surface profile changes. Experimental evidence was obtained that the transmission mode PA was due to the both recorded surface relief and volume polarization gratings whereas the reflection mode PA was due to the recorded surface relief gratings. The main PA features were similar for all three types of polarization gratings whereas details were different. PA properties of IWK-2D films were notably distinctive from those of previously studied films.</jats:p
Validating Pseudo-Free-Space Conditions in a Planar Waveguide Using Phase Retrieval from Fresnel Diffraction Patterns
No full textIn this study, we address the question of whether a waveguide with absorbing sidewalls can be considered pseudo free space and if the free-space transfer function is valid in such a medium. We test this hypothesis by applying a phase retrieval algorithm based on the free-space transfer function. First, optical measurements are carried out to measure the optical properties of a stack of thin films and select the parameters of simulations. Next, the propagation of light in a waveguide was simulated in COMSOL, and the phase of a wave was retrieved in MATLAB. Analysis was performed both for free-space conditions, and for a waveguide with absorbing sidewalls. The cross-correlation between the distributions of intensity under both conditions was about 0.40. The RMS error of the wave retrieved under free-space conditions was 0.378 rad, while that in the case of absorbing sidewalls was 0.323 rad, indicating successful retrieval. The successfully recovered phase of the input wave suggests that a waveguide with absorbing sidewalls can be approximated as pseudo free space and the free-space transfer function may be valid. These results may be used in future studies on how to shorten the phase retrieval of two-dimensional objects
A framework for validating AI in precision medicine : considerations from the European ITFoC consortium
No full textFunding Information: This work was supported by the ITFoC project (Information Technology for the Future of Cancer) – FLAG-ERA support. Publisher Copyright: © 2021, The Author(s).Background Artificial intelligence (AI) has the potential to transform our healthcare systems significantly. New AI technologies based on machine learning approaches should play a key role in clinical decision-making in the future. However, their implementation in health care settings remains limited, mostly due to a lack of robust validation procedures. There is a need to develop reliable assessment frameworks for the clinical validation of AI. We present here an approach for assessing AI for predicting treatment response in triple-negative breast cancer (TNBC), using real-world data and molecular -omics data from clinical data warehouses and biobanks. Methods The European “ITFoC (Information Technology for the Future Of Cancer)” consortium designed a framework for the clinical validation of AI technologies for predicting treatment response in oncology. Results This framework is based on seven key steps specifying: (1) the intended use of AI, (2) the target population, (3) the timing of AI evaluation, (4) the datasets used for evaluation, (5) the procedures used for ensuring data safety (including data quality, privacy and security), (6) the metrics used for measuring performance, and (7) the procedures used to ensure that the AI is explainable. This framework forms the basis of a validation platform that we are building for the “ITFoC Challenge”. This community-wide competition will make it possible to assess and compare AI algorithms for predicting the response to TNBC treatments with external real-world datasets. Conclusions The predictive performance and safety of AI technologies must be assessed in a robust, unbiased and transparent manner before their implementation in healthcare settings. We believe that the consideration of the ITFoC consortium will contribute to the safe transfer and implementation of AI in clinical settings, in the context of precision oncology and personalized care.Peer reviewe
