Fully integrated photonic continuous-variable quantum key distribution is a promising route toward compact and scalable secure optical links, yet the achievable transmission distance has been limited by the performance o...Fully integrated photonic continuous-variable quantum key distribution is a promising route toward compact and scalable secure optical links, yet the achievable transmission distance has been limited by the performance of integrated receiver chips and excess noise suppression methods. Here, we demonstrate a Gaussian-modulated continuous-variable quantum key distribution system with an integrated silicon photonic receiver, operating over 60 km. Enabled by a high-clearance, broadband silicon photonic receiver, in conjunction with a robust digital signal processing framework that utilizes a time-domain superposition algorithm and secure dynamic single-tap equalization, the system effectively achieves an asymptotic secret key rate of 1.68 Mbps, and a finite-size secret key rate of 0.80 Mbps at a data block length of 1.55×10. This work extends chip-based continuous-variable quantum key distribution to metropolitan-scale distances, confirming the viability of integrated receivers for large-scale quantum networks.
In our previous study, a home-built handheld OCT system was used to collect OCT images in vocal cord leukoplakia. First, 383 valid OCT images were collected from 12 patients with leukoplakia (including low-risk, high-ris...In our previous study, a home-built handheld OCT system was used to collect OCT images in vocal cord leukoplakia. First, 383 valid OCT images were collected from 12 patients with leukoplakia (including low-risk, high-risk, and malignant types). The best overall accuracy and recall were 92.59% and 93.25% for low-risk, high-risk, and malignant classification, by random forest (RF) model using 5-fold validation. However, low-risk dysplasia with a sensitivity of 87.72% could not meet clinical requirements. Here, we proposed an end-to-end joint learning model using optical coherence tomography (E2E-OCT) images for vocal cord leukoplakia diagnosis. The overall accuracy and recall improved by 5.58% and 4.87%, and especially the sensitivity for low-risk dysplasia improved from 87.72% to 97.48%. Notably, under leave-one-patient-out (LOPO) cross-validation, the model also maintained 96.64% sensitivity for low-risk dysplasia. The ablation experiments and explanation experiments demonstrated the robustness of our model.
Conventional holographic three-dimensional (3D) displays have a limited ability to enlarge their field of view (FOV) and cannot reconstruct panoramic 3D scenes. This paper proposes a method to overcome this limitation by...Conventional holographic three-dimensional (3D) displays have a limited ability to enlarge their field of view (FOV) and cannot reconstruct panoramic 3D scenes. This paper proposes a method to overcome this limitation by using a concave ellipsoidal mirror. The concave ellipsoidal mirror has two focal points and can converge wavefronts from its entire circumference to one focal point. Thus, a viewer located at the focal point can capture wavefronts in all directions, thereby achieving an omnidirectional FOV. To validate the proposed concept, we developed a prototype time-division system and demonstrated panoramic 3D scene generation with an FOV exceeding 270, far beyond the limited FOV of conventional holographic 3D displays.
Non-orthogonal multiple access (NOMA) combined with digital subcarrier multiplexing (DSCM) enables dense and flexible coherent passive optical networks (PONs). However, NOMA signal superposition biases pilot-aided carrie...Non-orthogonal multiple access (NOMA) combined with digital subcarrier multiplexing (DSCM) enables dense and flexible coherent passive optical networks (PONs). However, NOMA signal superposition biases pilot-aided carrier-phase recovery (CPR), while bandwidth-limited transceivers impose penalties on edge subcarriers. In this work, we propose a unified digital signal processing (DSP) framework that incorporates dual-pilot CPR with pair-wise maximum-ratio combining (MRC) across adjacent center-edge subcarrier pairs. By inserting pilots into both constituent signals of the superposed NOMA stream, the receiver builds a composite pilot reference that suppresses interference-induced phase bias. The resulting reliability estimate is then used to weight subcarrier branches in MRC, turning quality imbalance into diversity gain. In an experimental demonstration with an 80-Gbaud NOMA-DSCM coherent PON, the dual-pilot CPR achieves more robust phase recovery than conventional pilot-based and blind CPR baselines under NOMA-induced interference. With MRC enabled, the framework further delivers up to 2.29 dB SINR gain over benchmarks at low optical power, reducing average BER by 75.89% for ONU 1 and 30.33% for ONU 2.
Many applications that utilize whispering gallery mode resonators critically rely on the mode volume. In this work, we demonstrate a new, to the best of our knowledge, experiment to map the whispering gallery modes of a...Many applications that utilize whispering gallery mode resonators critically rely on the mode volume. In this work, we demonstrate a new, to the best of our knowledge, experiment to map the whispering gallery modes of a mm-sized disk resonator. Our technique relies on using a half-tapered fiber to excite the mode and a second half-tapered fiber to probe it. Our experimental results show a maximum intensity at zero polar angle with a width that agrees with that of the fundamental mode. Three-axis positioners control the spatial resolution in the polar direction. Differing from previous near-field tip-probe methods, the signal is coupled out of the resonator using a half-taper that is positioned in a tangential direction to the equator of the resonator disk. We match the models and simulations to the measured polar field profile and use the models to calculate the fundamental mode volume.
Interferometric scattering microscopy offers high sensitivity for nanoscale detection, but its quantitative capability remains constrained by multiple factors. Here, a quantitative framework is proposed for sparse-scatte...Interferometric scattering microscopy offers high sensitivity for nanoscale detection, but its quantitative capability remains constrained by multiple factors. Here, a quantitative framework is proposed for sparse-scatterer inspection scenarios using a dark-field interferometric configuration to suppress substrate-related background. Rather than relying on detailed interferometric patterns, the method extracts quantitative information from the axial redistribution of optical energy during propagation. Numerical simulations within this framework reveal a monotonic dependence of the characteristic axial-energy features on the diameter of subwavelength scatterers. Furthermore, experimental measurements under 532 nm illumination and statistical analysis show that the full width at half maximum of the axial energy concentration provides a strong size dependence for isolated nanoparticles in the 5-50 nm range, with group-level correlation (= 0.99985, RMSE = 0.0495) and nonparametric significance (= 0.0396).
An optical switch scheme based on large fan-in/fan-out multimode interference (MMI) couplers is proposed to enable compact, low-loss × switching with channel uniformity. Specifically, two identical 8 × 8 MMI couplers a...An optical switch scheme based on large fan-in/fan-out multimode interference (MMI) couplers is proposed to enable compact, low-loss × switching with channel uniformity. Specifically, two identical 8 × 8 MMI couplers are connected via equal-path-length waveguides to form an 8 × 8 silica switch. With CMOS-compatible fabrication, the switch demonstrates an insertion loss of 2.7 ± 0.6 dB and a crosstalk of -14.7 ± 4 dB across all switching scenarios at 1550 nm. The 3-dB bandwidth with crosstalk < -10 dB covers the wavelength range 1535 - 1565 nm (~C-band), which exactly coincides with the theoretical expectation. This scalable design breaks the constraints of traditional switches and facilitates high-density photonic integration.
In this Letter, we report a high-power, high-repetition-rate Ho:YLF chirped-pulse amplification (CPA) system driving a ZnGeP (ZGP) optical parametric generator and amplifier (OPG/OPA). The Ho:YLF CPA system operates at 1...In this Letter, we report a high-power, high-repetition-rate Ho:YLF chirped-pulse amplification (CPA) system driving a ZnGeP (ZGP) optical parametric generator and amplifier (OPG/OPA). The Ho:YLF CPA system operates at 100 kHz, delivering 48.1 W of average power at 2050.8 nm with a compressed pulse width of 5.0 ps. Using this source to pump the ZGP OPG/OPA, we obtain a 2.7 W signal light at 3402.1 nm and 0.64 W idler light at 5160.3 nm, with a pulse width of 2.5 ps for both. Moreover, continuous wavelength tuning ranges are achieved over 3051.2-3900.2 nm for the signal light and 4205.1-5160.3 nm for the idler light.
Near-infrared-II (NIR-II) fluorescence imaging offers high contrast and reduced scattering but lacks morphological context, posing challenges for precise pathological localization. Conventional fusion using heterogeneous...Near-infrared-II (NIR-II) fluorescence imaging offers high contrast and reduced scattering but lacks morphological context, posing challenges for precise pathological localization. Conventional fusion using heterogeneous camera arrays suffers from perspective-induced parallax and registration errors. Here, we present a background-enhanced NIR-II single-pixel imaging system for high-fidelity fluorescent localization and dynamic tracking. By employing a shared spatial encoding strategy with parallel silicon and InGaAs detectors, the system eliminates geometric distortions between background and fluorescence images, enabling precise localization without additional alignment algorithms. To address weak signal intensity in dynamic scenes, we further employed a bowl-shaped detector to enhance light collection efficiency, yielding a ~7-fold signal-to-noise ratio improvement. This enabled dynamic fluorescence tracking at 10 fps (sampling rate = 3.05%) with a physical pixel of 128 × 128. This work proposes what we believe to be a novel NIR-II imaging architecture that achieves precise localization and dynamic tracking of fluorescent signals within an anatomical background, offering a new solution for future surgical navigation.
We demonstrate a polymeric vertical coupler for optical redistribution applications. The device is fabricated using a hybrid-lithography process, combining ultraviolet (UV) lithography for a planar optical redistribution...We demonstrate a polymeric vertical coupler for optical redistribution applications. The device is fabricated using a hybrid-lithography process, combining ultraviolet (UV) lithography for a planar optical redistribution layer (ORDL) with two-photon polymerization (TPP) for the vertical coupling micromirrors. By leveraging the high refractive-index contrast between the core and cladding, we realized an all-solid total internal reflection (TIR) mirror, eliminating the need for complex metallization or air cavities. To ensure manufacturability, we incorporated a support structure into the coupler design. Theoretical study predicts coupling efficiencies of 89.4% and 81.6% for the unsupported and supported structures, respectively. Experimental characterization of the fabricated device demonstrates a coupling loss of approximately 3.3 dB at a telecommunication wavelength of 1310 nm. This work provides a scalable and cost-effective approach for integrating high-performance vertical interconnects into 3D photonic systems.
Ultrafast laser writing of single lattice defects in wide-bandgap semiconductors is shown to present a new, to the best of our knowledge, physical setting in which deeply subwavelength laser-writing positioning precision...Ultrafast laser writing of single lattice defects in wide-bandgap semiconductors is shown to present a new, to the best of our knowledge, physical setting in which deeply subwavelength laser-writing positioning precision is attainable but where the whole notion of positioning can only be understood in a statistical sense. We outline a framework for the analysis of this class of laser-matter interactions, grounding the concepts of optical super-resolution and subdiffraction positioning in statistical optics. Working along these lines, we derive closed-form solutions for physically meaningful quantifiers of laser-matter interactions on a subwavelength scale, suggesting a physically clear view of how deeply subdiffraction resolution can emerge from the interplay between determinism and stochasticity. We show that subdiffraction positioning precision in single-lattice-defect laser writing is achieved at the cost of a lower success rate, setting physical bounds on the scalability of integrated quantum photonic systems fabricated by means of super-resolving laser writing.
Britton M, Song H, Kincaid C
… +19 more, Brahms C, Cunningham E, Daniels A, Fang L, Gebhardt M, Kaufman B, Lantigua C, Larsen KA, Le Q, Lojo J, Neuhaus M, Robinson JS, Teodoro B, Travers JC, Tsao J, Chang Z, Chini M, Wu Y, Forbes R
We demonstrate nonlinear compression of mid-infrared pulses from a Cr:ZnSe chirped-pulse amplifier using a gas-filled stretched hollow-core fiber followed by bulk-material compression. Starting from 90 fs, 2.45 µm pulses...We demonstrate nonlinear compression of mid-infrared pulses from a Cr:ZnSe chirped-pulse amplifier using a gas-filled stretched hollow-core fiber followed by bulk-material compression. Starting from 90 fs, 2.45 µm pulses with 5.3 mJ energy, spectral broadening in the gas-filled capillary combined with optimized dispersion management enables compression to 15 fs, less than two optical cycles at 2.45 µm, with 3.3 mJ pulse energy, corresponding to a peak power of approximately 0.12 TW. The simplicity of the approach, based on a single hollow-core fiber stage and bulk dispersion compensation, makes it scalable to higher energies and establishes a robust route to mid-infrared drivers for high harmonic generation and attosecond applications.
Conventional geometric symmetry breaking for exciting quasi-bound states in the continuum (BICs) often induces spectral drift. Here, we propose an all-dielectric dimer metasurface that achieves orthogonal, decoupled cont...Conventional geometric symmetry breaking for exciting quasi-bound states in the continuum (BICs) often induces spectral drift. Here, we propose an all-dielectric dimer metasurface that achieves orthogonal, decoupled control of quasi-BIC and electromagnetically induced transparency (EIT) effects via spatial displacement. By utilizing horizontal and vertical offsets as independent degrees of freedom, we demonstrate that the radiation leakage of a toroidal-dipole-dominated first Brillouin zone (FBZ) induced quasi-BIC and the EIT bandwidth can be independently tuned while strictly maintaining resonant frequency stability. This spatial-coupling paradigm offers a robust platform for advanced multifunctional nanophotonics, including frequency-stable multi-channel sensing and slow-light devices.
Two-dimensional transition metal dichalcogenides are promising candidates for nonlinear photonics applications, offering strong nonlinear susceptibility and compatibility with integrated platforms. Although considerable...Two-dimensional transition metal dichalcogenides are promising candidates for nonlinear photonics applications, offering strong nonlinear susceptibility and compatibility with integrated platforms. Although considerable effort has been devoted to manipulating second harmonic generation in these materials, the dynamic control of nonlinear wavefronts remains largely unexplored. Metasurfaces have enabled significant progress in nonlinear beam engineering, yet their practical implementation is limited by low conversion efficiencies and restricted design flexibility. In this work, we employ feedback-based wavefront shaping using spatial light modulators to enhance SHG from pyramid-like WS multilayer structures by over three orders of magnitude in selected spatial regions. This approach allows us to program nonlinear holograms and dynamically shape the SHG signal through phase-only modulation, opening new possibilities for nonlinear imaging, optical information processing, and data communication.
Two-photon pumped lasers are pivotal for upconversion devices and nonlinear photonics, yet the realization of stable, high-gain media remains a significant challenge. Here, a thermal nanoimprint strategy to optimize MAPb...Two-photon pumped lasers are pivotal for upconversion devices and nonlinear photonics, yet the realization of stable, high-gain media remains a significant challenge. Here, a thermal nanoimprint strategy to optimize MAPbSnI perovskite films, while achieving simultaneous defect passivation and structural stability, is reported. The resulting films exhibit a two-photon absorption coefficient of 0.098 cm/GW at 1600 nm, enabling low-threshold amplified spontaneous emission of 137.2 μJ/cm under near-infrared (NIR) excitation at 1600 nm. A high net modal gain of 754 cm is extracted via variable stripe length measurements. Crucially, suppressed non-radiative recombination leads to markedly improved operational stability beyond 97 minutes. These results demonstrate that thermally nanoimprinted MAPbSnI may work as a promising gain medium for two-photon-pumped upconversion lasers.
We demonstrate an S-band thulium-doped fiber amplifier (TDFA) with an output power of ∼31 dBm and a noise figure (NF) of ∼4.94 dB at 1490 nm. The amplifier has a dual-stage configuration, in which homemade thulium-doped...We demonstrate an S-band thulium-doped fiber amplifier (TDFA) with an output power of ∼31 dBm and a noise figure (NF) of ∼4.94 dB at 1490 nm. The amplifier has a dual-stage configuration, in which homemade thulium-doped fluorotellurite fibers (TDFTFs) were used as the gain media, and a 1410/1570 nm dual-wavelength upconversion pump scheme was adopted. For the first-stage amplifier, the measured gain bandwidth (>20 dB) was ∼67 nm (1460-1527 nm), and the NF was <5 dB within this spectral range for a fixed input signal power of 0 dBm (1 mW). For the dual-stage amplifier, the gain bandwidth was measured to be ∼65 nm (1460-1525 nm) with a net gain of >30 dB and an NF of <6 dB. The measured maximum output power of the dual-stage amplifier was about ∼31 dBm at 1490 nm, corresponding to an optical-to-optical conversion efficiency of ∼16%. This represents the highest, to the best of our knowledge, output power achieved to date for S-band TDFAs. Our results indicate that the TDFTFs are promising gain media for developing S-band TDFAs with high-output-power and low-NF.
We present direct single-pass generation of polarization-entangled photon pairs near 810 nm in a domain-engineered nonlinear crystal pumped by a continuous-wave 405 nm laser. Despite operating outside the natural group-v...We present direct single-pass generation of polarization-entangled photon pairs near 810 nm in a domain-engineered nonlinear crystal pumped by a continuous-wave 405 nm laser. Despite operating outside the natural group-velocity matching regime, the source produces high-quality polarization entanglement with a Clauser-Horne-Shimony-Holt parameter of =2.764±0.002. We further exploit the intrinsic phase sensitivity of the entangled state to perform nonlocal, wavelength-dependent retardance measurements of birefringent waveplates through two-photon polarization correlations. Our results establish a high-performance alternative to conventional polarization entanglement sources, combining room-temperature silicon-detector compatibility, compactness, and spectral flexibility, in a practical platform for phase-sensitive quantum metrology.
Perceiving non-Lambertian surfaces with specular reflection is challenging. Event cameras, with high dynamic range, temporal resolution, and low data redundancy, offer a promising 3D sensing tool, but specular reflection...Perceiving non-Lambertian surfaces with specular reflection is challenging. Event cameras, with high dynamic range, temporal resolution, and low data redundancy, offer a promising 3D sensing tool, but specular reflections still produce dense, spatio-temporally aliased event streams that obscure surface features and hinder reliable event-based 3D sensing. This Letter presents a hardware-software co-design method for removing reflection interference. A strobed fluorescence apparatus actively modulates surface feature signals, inducing pronounced differences in event polarity and spatio-temporal distribution compared with reflection noise. Within each strobing period, events are filtered based on polarity consistency and spatio-temporal characteristics, enabling effective signal-to-noise separation. Thus, robust 3D sensing is achieved with clean encoded signals. Experiments show that the proposed method suppresses reflection interference and preserves surface details better than existing light denoising methods, achieving sensing accuracy comparable to frame-based camera systems.
The nonlinear dynamics of transverse and polarization modes of a broad-area vertical-cavity surface-emitting laser (BA-VCSEL) exhibit, without any external perturbation, chaos with high correlation dimension, large bandw...The nonlinear dynamics of transverse and polarization modes of a broad-area vertical-cavity surface-emitting laser (BA-VCSEL) exhibit, without any external perturbation, chaos with high correlation dimension, large bandwidth (BW), and good spectral flatness over a wide range of currents. We leverage this for high bit-rate entropy generation and random number generation (RNG), passing the NIST tests with rates up to 150 Gb/s, and observe a correlation between the correlation dimension and the number of passed NIST tests. The RNG shows consistent performance across a wide range of parameters. In contrast to other setups, our system does not require optical feedback or optical injection to generate chaos, making it simple, compact, and robust.
Lutetium oxide (LuO) single-crystal fibers represent a promising platform for extreme-environment optics, offering an exceptionally high melting point (~2450 °C) and a cubic crystal structure that avoids polarization-dep...Lutetium oxide (LuO) single-crystal fibers represent a promising platform for extreme-environment optics, offering an exceptionally high melting point (~2450 °C) and a cubic crystal structure that avoids polarization-dependent effects associated with birefringent crystalline fibers such as sapphire. In this work, we demonstrate the first-ever, to the best of our knowledge, inscription of a fiber Bragg grating (FBG) in Lu₂O₃ single-crystal fiber using a femtosecond (fs) laser line-by-line technique. The fabricated LuO FBG, when spliced to a standard silica interrogation network with a 0.46 dB coupling loss, exhibits a stable spectral response and reversible operation up to 1663 °C. The measured thermal sensitivity of 14.4 pm/°C at 1663 °C is approximately 50% lower than that of a comparable sapphire-based FBG. This reduced sensitivity effectively decreases the thermally induced spectral excursion per sensor, thereby alleviating spectral overlap constraints and potentially increasing the achievable multiplexing density within a fixed interrogation bandwidth. These results establish Lu₂O₃ single-crystal fibers as a viable ultrahigh-temperature sensing platform for high-density distributed sensing applications in aerospace, energy, and other high-temperature industrial environments.