Invited Speakers

Abstract: Minimizing optical reflection across wide spectral ranges and incident angles remains a key challenge in advanced optical systems—particularly when environmental stability, material compatibility, and multifunctionality are required. In this contribution, we present several strategies for combining broadband, angle-insensitive, and system-specific anti-reflective (AR) surfaces with volumetric modifications, employing gradient-index architectures, and adapting to different material platforms.

About the Speaker:  Prof. Dr. Robert Brunner’s research has always focused on the interaction of light with small structures. After completing his PhD in the field of near-field optical microscopy, he led the "Microstructured Optics" laboratory at the Research and Technology Center of Carl Zeiss for more than a decade. During this time, he gained extensive experience in direct-write laser lithography, interference lithography, and dry-etching techniques for the fabrication of refractive micro-optics, spectroscopic gratings, diffractive imaging elements, and nanostructured anti-reflective coatings. In 2010, he was appointed Professor of Applied Optics at the University of Applied Sciences Jena, Germany. His current research focuses on the development and investigation of new concepts in micro-optical systems, particularly for use in hybrid imaging (refractive-diffractive), spectral sensing, and multi- or hyperspectral imaging. He has deep expertise in the fabrication of micro- and nano-optical structures and is also actively involved in biomimetic optics research.

Abstract:  Direct laser writing (DLW) with ultrafast lasers has become a staple technology for advanced material processing. However, one highly sought yet underdeveloped application is the direct recording of diffractive optical elements (DOEs) in dielectric materials. The challenge to precisely control the spatial phase distribution is successfully demonstrated only in bulk recording, where laser-induced tiny changes in optical properties can be accumulated with multilayer processing. While effective, this method is time-consuming and significantly limits design flexibility.  Using ultraviolet wavelengths in femtosecond microprocessing offers several advantages over longer IR pulses. Most notably, UV processing achieves better focusability with low numerical aperture optics, enabling the creation of smaller feature sizes (<10 μm) with conventional high-speed laser scanning setups. 

About the Speaker: Prof. Domas Paipulas is a scientist with extensive experience in femtosecond micromachining and serves as the group leader of the Femtosecond Micromachining Laboratory at Vilnius University’s Laser Research Center (LRC) in Lithuania. He has been working in this field since 2007 and has played a key role in establishing the femtosecond machining laboratory at LRC. His primary research focus is on "Femtomachining for Photonics Applications," which includes employing ultrafast lasers for laser micromachining, studying light-matter interactions, developing integrated photonics, designing optical systems, and more. He has published over 60 papers and is the co-author of two European patents.

About the Speaker:  Etienne Brasselet is Research Director at CNRS, Laboratoire Ondes et Matière d’Aquitaine, University of Bordeaux, France. His scientific interests cover wave-matter interactions in the framework of multidisciplinary environment including nonlinear phenomena, optics and photonics, acoustics, mechanical effects of waves using either solid or soft matter systems such as liquid crystals. His research activities mainly focus on situations where structured fields meet structured matter, which makes topology and vector fields at play.

Dr.  Igor Shevkunov
Senior researcher from Tampere University, Finland

Abstract:  Diffractive optical elements (DOE) have appeared as an alternative to conventional refractive optics to overcome its limitations (e.g. chromatic aberration, low spectral resolution, and shallow depth-of-field), and to enable novel functionalities possible due to a potential of these lenses to nearly arbitrary modulation of light. Imaging with DOEs can be considered as a combination of three layers: ’physical layer’ (optical light beam coding and propagation), ’theoretical layer’ (mathematical model of the imaging system for a given optical setup), and ’computational layer’ (algorithmic decoding and imaging). To optimize the optics and imaging based on these three layers, end-to-end optimization is required. Having the possibility to include DOE in the optimization procedure is a great advantage that allows for overcoming discrepancies between theory and practice, this approach is called ‘hardware in the loop’ (HIL). We propose to use DOEs on a smart material, which is capable of changing its shape in a loop. We demonstrate extended-depth-of-field imaging by the proposed approach.

About the Speaker: Igor Shevkunov is a senior researcher from Tampere University, Finland. He has expertise in digital holography and computational imaging, in a wide range of topics from single wave holography to hyperspectral image detection with development of state-of-the-art imaging and processing techniques.

Abstract:  Due to their ability to maintain coherent quantum states with minimal energy loss, superconductors are essential for building quantum components, while photons are ideal carriers of quantum information, offering high-speed and low-loss transmission capabilities. However, integrating the two quantum platforms poses significant challenges due to the inherent damping of photonic states when interacting with conventional superconductors. Therefore, creating transparent superconductors would be an ideal solution to improve the overall performance of a hybrid system minimizing photonic attenuation. This field is in its infancy, but some basic principles that allow the coexistence of quite satisfactory transparency for visible light with the superconductivity of itinerant electrons have been developed. In this contribution, I present the strategy for reaching the best compromise which involves two steps - creating a transparent conductor with a sufficiently high concentration of mobile carriers and transferring it to a superconducting state. Our studies focused on doped indium-tin oxide (ITO) layers have used two ways leading to the superconducting state: electrochemical intercalation and synthesis of oxygen-deficient ITO films. Both methods enable precise tuning of the superconducting onset temperature T_c over a wide range of 1 - 5 K, while maintaining optical transparency between 30 and 85%. Two-dimensional superconductivity was found in electrochemically reduced ITO strips while ITO films sputtered under oxygen-deficient conditions exhibited three-dimensional characteristics. The dome-shaped behavior of T_c and the decrease in transparency with increasing charge carrier concentration allow the selection of the necessary combination of the two factors for specific applications.

About the Speaker:  Candidate of Phys. & Math. Sci. (PhD) in Solid State Physics, 1976, Doctor of Phys. & Math. Sci. (Dr. Honor.) in Solid State Physics, 2013, both from the Donetsk Institute for Physics and Engineering, Donetsk, Ukraine; Professor in Applied Physics and Nanomaterials, 2017, Institute for Metal Physics, Kyiv, Ukraine. Since 2022, he has been a leading researcher at the Kyiv Academic University, Kyiv, Ukraine. In 2023, he was awarded a three-year European Union grant to work as a researcher at the Centre for Nanotechnology and Advanced Materials, Comenius University Bratislava, Slovakia. According to the Scopus database, he is the author of 167 papers in the fields of superconductivity, quantum transport, and quantum materials. He actively collaborates with colleagues from the Friedrich Schiller University Jena, Germany, Northwestern University, Evanston, USA, and the University of Texas at Dallas, TX, Richardson, USA. He is Vice-President of the Ukrainian Physical Society and a member of the American Physical Society.

Abstract:  This talk provides a comprehensive review of IHLLS microscopy from the perspective of optics. Emphasis is placed on the advantages that IHLLS detection arm configurations present, given the degree of freedom gained by uncoupling the excitation arm of the LLS microscope and the IHLLS detection arm but keeping the z-galvo scanning for both detection systems. The new imaging properties are first highlighted in terms of optical parameters and how these have enabled biomedical applications. Then, based on the multiple possibilities for generating the LS/LLS in the microscope (using Gaussian and Bessel beams), a systematic comparison of their optical performance is presented. Finally, the novel optical implementations in the IHLLS detection arm, enabled by advances in optics and photonics, are highlighted. These advancements allow for new ways of creating and using light sheets in microscopy, particularly in areas like biomedical imaging.

About the Speaker: Mariana Potcoava is a dedicated research scientist with 25 years of hands-on R&D experience in academia and in industry. Her experience involves programming, theoretical and practical work in optics, spectroscopy, lasers, image processing, and complex optical instrumentation development for biomedical research areas. Throughout her work, she has pursued research to design and build optical instrumentation, requiring the integration of various electro-optics subsystems for imaging characterization, with micrometer and nanometer resolution. As a graduate student in applied physics at the University of South Florida (2009), she built a digital holographic microscope for human eye retinal scanning with micrometer resolution. During her employment at the 3i company (2015-2016), she worked with dedicated professionals to build multiple lattice light-sheet microscopes (LLSM) at 3i’s office and in the field, which gave her better skills in building commercial microscopes. Returning to academia at the University of Illinois at Chicago (UIC), she built a custom version of LLSM to provide a previously unavailable live cell imaging resource for the UIC research community. Her current research at UIC is to develop technologies to improve the resolution of the LLSM and other 3D-resolved fluorescent microscopes to help researchers and medical professionals better understand diseases at a molecular level, which could lead to improved diagnostics and therapeutic strategies.

Abstract:  Optical vortices have gained significant attention due to their potential to carry a well-defined orbital angular momentum (OAM) [1]. The size of these vortex beams depends on the embedded topological charge (TC), which limits their efficiency for several applications. To address this limitation, Ostrovsky and his co-workers introduced the concept of Perfect Optical vortex (POV) beams [2]. These POV beams exhibit a TC independent annular intensity profile.  Later, Vaity et al demonstrated that these POV beams are the Fourier transform of the Bessel Gaussian (BG) beams [3], enabling a simpler generation method and resolving long‑standing uncertainty by fulfilling the demand for a vortex beam immune to TC. Leveraging this concept, researchers produced a double‑ring POV beams via the Fourier transform of azimuthally polarized BG beams [4]. The azimuthal polarization decomposes into right‑ and left‑circularly polarized components with shifted TCs, yielding two concentric rings of identical intensity but different radii. Since optical vortices are renowned for their ability to trap particles, a double‑ring POV can trap particles in the region between the two rings. However, this method lacks any parameter to control the spacing between two rings and requires precise polarization control, complicating its implementation. To address this, here, we introduce and demonstrate a novel approach for generating double‑ring POV beams by modifying the phase of a Bessel-Gaussian beam with a conical phase. Through both theoretical analysis and experimental validation, we demonstrate precise, independent control over the ring’s radius and the spacing between the two rings, enhancing their versatility across a range of applications.

About the Speaker: Dr. Kumar is an Assistant Professor at the Department of Physics, SRM University-AP, Andhra Pradesh, India. He received his master’s and PhD degree in Physics from IIT(ISM) Dhanbad in 2015 and June 2018, respectively. Before joining SRM-AP, he was a Postdoctoral Research Fellow at Electro-optics Laboratory, Ben-Gurion University of the Negev, Israel for two years (2020-2022). Prior to that, he was a postdoctoral research fellow at Smart Computational Imaging Laboratory, Nanjing University of Science and Technology, China, for one year (2019-2020) and National University of Singapore (NUS), Singapore for one year (2018-2019). He is a member of OPTICA (formerly OSA) and life fellow member of Optical society of India. He has authored or co-authored more than 50 papers in various international journals. His research interests include optical image encryption, digital holography, computational imaging, structured light beams, and biomedical optics.

Dr.  Tatsuki Tahara
National Institute of Information and Communications Technology (NICT), Japan

Abstract:  We present digital holography techniques with daily-use light in which multidimensional information such as three-dimensional (3D) space, time, phase, and wavelength are obtained as speckleless holograms. Exploiting self-interference incoherent digital holography, single-shot phase-shifting interferometry, and a polarimetric image sensor, we have proposed fully-passive single-shot full-color digital holography, developed portable natural-light digital holography systems, and performed natural-light full-color digital motion-picture holographic imaging. We also developed speckleless holography in which self-reference holography, a commercially available light-emitting diode, and the designed coded phase aperture are utilized for quantitative phase imaging of transparent objects in 3D space. We show these digital holography techniques and experimental results obtained with the holography techniques.

About the Speaker:  Dr. Tatsuki Tahara received the B.E., M.E., and D.E. degrees in electronics and information science from Kyoto Institute of Technology, Kyoto, Japan, in 2007, 2009, and 2013, respectively. He was a Research Fellow with Japan Society for the Promotion of Science (JSPS), from 2011 to 2013; an Assistant Professor with the Faculty of Engineering Science, Kansai University, Osaka, Japan, from 2013 to 2018; a Specially-Appointed Associated Professor with the National Institute of Informatics (NII), Tokyo, Japan, from 2018 to 2019; and a Researcher with Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), from 2016 to 2020. He was also a Researcher with the National Institute of Information and Communications Technology (NICT), Tokyo, from 2019 to 2021, where he has been a Senior Researcher, since 2021. His research interests include incoherent digital holography, fully-passive natural-light holography, phase-shifting interferometry, digital holography, and development of digital holography apparatus. He was a Topical Editor of Applied Optics (OPTICA) from 2017 to 2023. He is an editorial board of Journal of Optics (IOP Publishing) since 2021.

Abstract:  The authors review the recent advances of the parallel phase-shifting digital holography (P-PSDH) and the parallel transport of transport-of-intensity equation (P-TIE). To obtain complex amplitude images, it is generally necessary to record multiple images. Both P-PSDH and P-TIE, on the other hand, record these multiple images in parallel. Three-dimensional (3D) imaging of refractive index distribution of dynamic gas flow and the 3D imaging of the temperature distribution of heated air have been demonstrated by P-PPSD. Furthermore, movies of sound wave propagation with 100,000 frames per second (fps) have been obtained. Also, high-speed multiplane imaging and quantitative phase imaging of dynamic air induced by air discharge was demonstrated by P-TIE using incoherent light. In both techniques, complex amplitude images are recorded at 1,000,000 fps each.

About the Speaker: Yasuhiro Awatsuji received the BE, ME and DE degrees in applied physics from Osaka University, in 1992, 1994 and 1997, respectively. He has been a Professor with Faculty of Electrical Engineering and Electronics, Kyoto Institute of Technology since 2014. His research interests are in the area of information optics with emphasis on holography. He is also interested in the area of 3D display, 3D measurement, quantitative phase imaging, microscopy, visualization of invisible objects, high-speed imaging, and ultrafast imaging. He is a senior member of Optica and SPIE.

Prof.  Natan T. Shaked 
Professor and the Chair of the Department of Biomedical Engineering at Tel Aviv University, Israel

Abstract:  Label-free optical imaging employs nondestructive approaches to visualize biomedical samples. It utilizes endogenous intrinsic signals, rather than specific exogenous markers (e.g., fluorescent markers) or genetic modifications. Exogenous labeling or genetic modifications perturbs the natural biological processes, dynamics and response of live cells, degrades the vitality of the sample and might be fatal in longer-term longitudinal studies. Typically, it is not allowed in cases where the cells need to be used for further treatments, such as inspection of drugs on the isolated cells for personalized medicine and treatment or on human sperm cells during in vitro fertilization (IVF). In general, label-free imaging spares the use of expensive labeling agents and is a more general and natural approach than label-based imaging, especially if for cases where specific exogenous markers characterizing the pathology of interest are not known or do not exist. Importantly, label-free imaging provides layers of information typically missed in regular imaging, potentially enabling new medical diagnosis tasks.

Abstract:  We present both numerical and experimental advances in high-throughput label-free lensless computational imaging for two- and three-dimensional biomedical applications. Our focus is on novel lensless holographic techniques enabling large-volume, high-content, stain-free imaging of both amplitude and quantitative phase of unimpaired bio-samples. These approaches are particularly well-suited for in-depth analysis of cells and tissues, offering scalable solutions for next-generation biomedical diagnostics. We demonstrate the capabilities of these methods through high-precision validation using static phantoms fabricated via two-photon polymerization and real-life challenging imaging of fixed biological tissue slices and cell cultures and time-lapse examination of dynamic live cells. Finally, we outline key challenges and opportunities ahead in pushing the frontiers of large-volume label-free 2D/3D quantitative phase imaging.

About the Speaker: Maciej Trusiak is an Associate Professor at the Institute of Micromechanics and Photonics, Faculty of Mechatronics, Warsaw University of Technology. He earned his B.Sc., M.Sc., and Ph.D. degrees in Photonics Engineering from the same university in 2011, 2012, and 2017, respectively. Following his doctoral studies, he completed a one-year postdoctoral fellowship in the Optoelectronic Image Processing Group led by Prof. Javier García and Prof. Vicente Micó at the University of Valencia, Spain. In 2022, he obtained his habilitation degree and launched the Quantitative Computational Imaging Lab (qcilab.mchtr.pw.edu.pl), focusing on computational imaging, lensless microscopy, optical metrology, interferometry and holography, quantitative phase imaging, and fringe pattern analysis. In 2023, he was awarded the ERC Starting Grant for research on lensless, label-free nanoscopy. Prof. Trusiak is an active member of the optical science community. He is a Senior Member of SPIE and Optica, and served on the SPIE Award Committee, acting as Chair of the Maria Goeppert-Mayer Award in Photonics Sub-Committee and Member of the Chandra Vikram Award in Optical Metrology Sub-Committee. He has held various organizational roles, including Co-Chair and Committee Member of the SPIE Interferometry and Structured Light Conference at SPIE Optics + Photonics 2022 and 2025, and Chair of the Warsaw Summer School for Advanced Optical Imaging 2024. He is also a Scientific Committee Member of Computational Optical Sensing and Imaging (COSI) at the Optica Imaging Congress 2024 and 2025. He currently serves as Associate Editor for Applied Optics (Optica Publishing Group) and Optics and Lasers in Engineering (Elsevier), Executive Editorial Board Member for Journal of Physics: Photonics (IOP), and Editorial Board Member for Advanced Devices & Instrumentation (AAAS Science Partner Journal). He also reviews for numerous high-impact journals in the optics & photonics field.