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Nonlinear optical processing of ambient natural light is highly desired for computational imaging and sensing. Strong optical nonlinear response under weak broadband incoherent light is essential for this purpose. By merging 2D transparent phototransistors (TPTs) with liquid crystal (LC) modulators, we create an optoelectronic neuron array that allows self-amplitude modulation of spatially incoherent light, achieving a large nonlinear contrast over a broad spectrum at orders-of-magnitude lower intensity than achievable in most optical nonlinear materials. We fabricated a 10,000-pixel array of optoelectronic neurons, and experimentally demonstrated an intelligent imaging system that instantly attenuates intense glares while retaining the weaker-intensity objects captured by a cellphone camera. This intelligent glare-reduction is important for various imaging applications, including autonomous driving, machine vision, and security cameras. The rapid nonlinear processing of incoherent broadband light might also find applications in optical computing, where nonlinear activation functions for ambient light conditions are highly sought.
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http://dx.doi.org/10.1038/s41467-024-46387-5 | DOI Listing |
ACS Photonics
August 2025
Nanophotonic Systems Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, Tannenstrasse 3, Zurich 8092, Switzerland.
Interferometric-based microscopies stand as powerful label-free approaches for monitoring and characterizing chemical reactions and heterogeneous nanoparticle systems in real time with single-particle sensitivity. Nevertheless, coherent artifacts, such as speckle and parasitic interferences, together with limited photon fluxes from spatially incoherent sources, pose an ongoing challenge in achieving both high sensitivity and throughput. In this study, we systematically characterize how partial coherence affects the signal contrast and background noise level in inline holography microscopes operated in a reflection geometry, a category that encompasses interferometric scattering microscopy (iSCAT).
View Article and Find Full Text PDFNano Lett
September 2025
Laboratory for Mechanics of Materials and Nanostructures, Empa, Swiss Federal Laboratories for Materials Science and Technology, Thun 3602, Switzerland.
Disordered metasurfaces offer unique properties unattainable with periodic or ordered metasurfaces, notably the absence of deterministic interference effects at specific wavelengths and angles. In this work, we introduce a lithography-free nanofabrication approach to realize cascaded disordered plasmonic metasurfaces with submicrometer total thickness. We experimentally characterize their angle-resolved specular and diffuse reflections using the bidirectional reflection distribution function and develop accurate theoretical models that remain valid even at large incidence angles.
View Article and Find Full Text PDFIEEE Trans Image Process
January 2025
Because optical spectrometers capture abundant molecular, biological, and physical information beyond images, ongoing efforts focus on both algorithmic and hardware approaches to obtain detailed spectral information. Spectral reconstruction from red-green-blue (RGB) values acquired by conventional trichromatic cameras has been an active area of study. However, the resultant spectral profile is often affected not only by the unknown spectral properties of the sample itself, but also by light conditions, device characteristics, and image file formats.
View Article and Find Full Text PDFThis paper proposes a method for incoherent beam combining on extended areas (or extended targets) based on a gradient light intensity trap, which is effectively created through intensity weighted modulation, and with the help of a proper optimization algorithm, light spots will be guided into this trap to achieve beam combination. A physical model of this method is established, which determines the optimal surface profile of the gradient light intensity trap, thereby aiding in achieving ideal results for multi-channel beams in both modulation and non-modulation. Subsequently, the feasibility of the method is verified in the laboratory, where tip/tilt aberrations are corrected by adaptive fiber-optics collimators during the beam-combining process.
View Article and Find Full Text PDFOpt Express
February 2025
Speckle imaging through single multimode fibers (MMFs) has garnered significant attention for its minimally invasive nature and high imaging resolution. However, the prevalent fully serial sampling approach severely limits imaging speed. Here, we propose, to our knowledge, a novel method for achieving fast and high-resolution speckle imaging via optical coherence control.
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