Light field (LF) denoising is pivotal for enhancing downstream LF applications. However, most existing methods focus primarily on removing noise signals, lacking sufficient preservation and utilization of the intrinsic s...Light field (LF) denoising is pivotal for enhancing downstream LF applications. However, most existing methods focus primarily on removing noise signals, lacking sufficient preservation and utilization of the intrinsic structural consistency of LF, which leads to suboptimal denoising performance and compromised geometric relationships. To this end, we propose a collaborative multi-stage attention mechanism that integrates complementary cues from residuals, geometric constraints, and global information. Specifically, first, we design a residual-driven channel attention module to leverage residual analysis for coarse denoising; second, an epipolar-guided cross attention module to explicitly preserve structural consistency across views by leveraging epipolar constraints; and finally, a global domain refinement module that performs deep optimization of texture and structure via multi-head self-attention. Experiments on synthetic and real-world LFs demonstrate that the proposed method maintains the consistency of LF structure and simultaneously outperforms state-of-the-art methods in denoising performance.
We present a generalized analytical framework for characterizing the isolation performance of microwave photonic circulators under both small- and large-signal conditions. Validated using a system comprising a laser diod...We present a generalized analytical framework for characterizing the isolation performance of microwave photonic circulators under both small- and large-signal conditions. Validated using a system comprising a laser diode, an electro-optic phase modulator, and a photodetector, the model evaluates isolation by applying radio-frequency signals to both ends of the modulator electrode and analyzing the output power spectrum. Experimental results show that, under small-signal operation (modulation index = 0.18), the measured isolation agrees with conventional transmit-isolating photonic receiver (TIPRx) theory. More notably, under large-signal operation ( = 3.20), isolation improves by 3 dB. Communication tests further confirm that crosstalk from the transmitted signal is significantly suppressed in the large-signal regime compared to the small-signal case. This versatile model provides a unified tool for analyzing and optimizing microwave photonic circulators across diverse operating conditions.
Single-pixel imaging enables high-sensitivity measurements across diverse spectral regimes. However, reconstructing high-quality dynamic color scenes under sub-Nyquist sampling remains challenging due to the trade-off be...Single-pixel imaging enables high-sensitivity measurements across diverse spectral regimes. However, reconstructing high-quality dynamic color scenes under sub-Nyquist sampling remains challenging due to the trade-off between spatiotemporal resolution and reconstruction fidelity. This article proposes a dynamic color Fourier single-pixel imaging framework that integrates a multi-channel acquisition scheme with a joint-prior reconstruction model to address this challenge. A hyper-Laplacian prior is employed to exploit cross-channel correlations, while a local low-rank prior captures temporal redundancy in dynamic scenes. Compared to a single prior, the joint approach enables mutual reinforcement between the two priors. Based on this formulation, we derive an efficient alternating minimization scheme that achieves significantly accelerated convergence through closed-form solutions. Experimental results demonstrate that the proposed method yields a PSNR improvement of over 5 dB compared to conventional Fourier single-pixel imaging, while maintaining robust reconstruction within 92 ms per frame.
Accurate three-dimensional flow-field measurement is vital for diagnostics in aerospace, combustion, and thermal processes. We present a multi-view phase measurement deflectometry (PMD) method for volumetric temperature-...Accurate three-dimensional flow-field measurement is vital for diagnostics in aerospace, combustion, and thermal processes. We present a multi-view phase measurement deflectometry (PMD) method for volumetric temperature-field reconstruction. By encoding absolute screen coordinates in fringe phases, PMD determines ray directions on a pixel-wise basis, ensuring intrinsic geometric self-consistency between the deflection measurement and the 3D reconstruction without relying on cross-correlation operations. A chain-based joint calibration strategy with anchor cameras accommodates surround-view configurations lacking a global common field of view. The tomographic inverse problem is solved within an alternating direction method of multipliers framework incorporating total-variation regularization and visual-hull support constraints. Numerical simulations and experiments on a thermal plume validate the proposed method, with thermocouple comparison showing a mean absolute relative difference of 1.87% and a mean absolute difference of 26.3 K, offering a new, to the best of our knowledge, pathway toward high-resolution volumetric flow diagnostics.
Dynamic wavelength modulation of semiconductor lasers is widely used for rapid spectral scanning, yet its intrinsic temporal dynamics are rarely exploited as a basis for sensing feature construction. Here, we propose the...Dynamic wavelength modulation of semiconductor lasers is widely used for rapid spectral scanning, yet its intrinsic temporal dynamics are rarely exploited as a basis for sensing feature construction. Here, we propose the adiabatic dynamic turning point (ADTP), a time-domain physical criterion that emerges during dynamically chirped laser excitation. Unlike conventional dispersion turning points governed by structural dispersion, ADTP originates from a stationary condition in the wavelength tuning trajectory and appears as a distinct temporal feature in optical responses. Through theoretical analysis, simulations, and experiments with fiber interferometric sensors, we show that the ADTP region provides identifiable temporal signatures enabling direct tracking of sensing information derived from periodic interferometric responses, without explicit spectral reconstruction. Temperature sensing experiments confirm bidirectional temporal shifts and sensitivity enhancement near the ADTP. Time-division multiplexed multipoint sensing is further demonstrated, highlighting the potential of ADTP as a source-defined feature mechanism for time-domain optical sensing.
We propose a scheme for two-dimensional image storage based on optomechanically induced transparency in a hybrid opto-electromechanical system comprising a cavity optomechanical system and a tunable capacitor. This schem...We propose a scheme for two-dimensional image storage based on optomechanically induced transparency in a hybrid opto-electromechanical system comprising a cavity optomechanical system and a tunable capacitor. This scheme is a fully opto-electromechanical two-dimensional image storage mechanism that is independent of atomic ensembles. The charged mechanical oscillator serves as the coupling interface between these two subsystems. Analytical and numerical results show that the optomechanical coupling strength in the cavity optomechanical system significantly influences the storage performance of two-dimensional images. When the optomechanical coupling strength is fixed, the storage efficiency can be further improved and optimized by modulating the external voltage applied to the capacitor. The proposed scheme holds promise for applications in two-dimensional image information storage and high-fidelity quantum storage in quantum information processing.
We propose an integrated transmission scheme for data center interconnects (DCIs) that jointly enables security and monitoring at the physical layer. A perception-embedded modulation (PEM) method is designed to embed dev...We propose an integrated transmission scheme for data center interconnects (DCIs) that jointly enables security and monitoring at the physical layer. A perception-embedded modulation (PEM) method is designed to embed device identifiers into modulated data, while channel anomalies are sensed based on the statistical characteristics of the constellation same-set ratio. To protect both the transmitted data and the embedded identifiers, chaotic noise injection is introduced, and reliable transmission of the masked signal is ensured through delta-sigma modulation (DSM). The proposed chaotic PEM-DSM encrypted signal at 64 GBaud is validated over a 240 km optical fiber link. The results demonstrate that the scheme achieves secure data transmission, accurately identifies unauthorized devices, and enables optical performance monitoring with a resolution of 1 dB.
We propose and experimentally demonstrate a high-efficiency cascaded Raman structured-light laser based on a Ba(NO) crystal. By combining a non-collinear V-shaped resonator with large-mode-area pumping and mode-size matc...We propose and experimentally demonstrate a high-efficiency cascaded Raman structured-light laser based on a Ba(NO) crystal. By combining a non-collinear V-shaped resonator with large-mode-area pumping and mode-size matching to high-order Stokes eigenmodes, the spatial overlap between the pump and target Stokes fields is improved, enabling enhanced Raman gain extraction and efficient cascaded conversion of high-order structured modes. High-quality one-dimensional Hermite-Gaussian (HG) modes up to the 20th order and two-dimensional HG modes are generated, together with direct intracavity generation of a first-order Laguerre-Gaussian (LG) mode and extracavity conversion to higher-order LG modes. At the second-Stokes wavelength of 1369 nm, the HG modes achieve a maximum pulse energy of 0.55 mJ with a conversion efficiency above 35%, while the directly generated LG mode reaches 0.64 mJ with a maximum conversion efficiency of 42%. The structured Raman output also preserves pulse compression, with durations 1-2 ns shorter than those of the pump. This work provides an effective route for high-efficiency wavelength extension of high-energy structured light.
Weak value amplification (WVA) has emerged as a powerful technique that enhances measurement precision. However, traditional table-top WVA setups and on-chip demonstrations have not achieved an amplification over 20 dB....Weak value amplification (WVA) has emerged as a powerful technique that enhances measurement precision. However, traditional table-top WVA setups and on-chip demonstrations have not achieved an amplification over 20 dB. The practical limit of the amplification is the fidelity of photon post-selection. To address this limit, we design a weak value device with an over 30 dB interferometer extinction ratio, where the stray light in the dark port is minimized with thermally tunable phase shifters. As a result, the device successfully shows 30 dB WVA, termed ultra-high WVA. This WVA optimization strategy by improving interferometer extinction is extensible to a wide range of WVA-based detections, paving the way for their broader application in practical precision measurements.
We propose an ultrahigh-sensitivity directional torsion sensor based on a Michelson interferometer configured with a helical asymmetric twin-core fiber (ATCF). The sensor structure integrates a helical ATCF, a thermally...We propose an ultrahigh-sensitivity directional torsion sensor based on a Michelson interferometer configured with a helical asymmetric twin-core fiber (ATCF). The sensor structure integrates a helical ATCF, a thermally diffused 3-dB coupler, and a gold reflective film, with the central core serving as the reference arm and the eccentric core as the sensing arm. Torsion test results show that the sensor achieves a maximum sensitivity of -17.55 nm/(rad/m). It realizes clear discrimination of torsion direction by distinguishing the blue/red shifts corresponding to clockwise/counterclockwise torsion. The temperature cross-sensitivity is as low as -0.016 (rad/m)/°C owing to the dual-core design, experiencing nearly identical thermal expansion. Compared with reported fiber torsion sensors, this sensor features a compact structure, low cost, and high stability, holding great application potential in fields such as structural health monitoring and precision manufacturing.
Measurement of two-dimensional angle-resolved optical scattering (TAOS) patterns is an attractive technique for detecting and characterizing micron-sized high-speed flying particles. The elastic-scattering intensity patt...Measurement of two-dimensional angle-resolved optical scattering (TAOS) patterns is an attractive technique for detecting and characterizing micron-sized high-speed flying particles. The elastic-scattering intensity pattern from a single particle as a function of spherical coordinate angles and provides detailed information on the particle's morphology. By use of an ellipsoidal reflector and a high-speed CCD camera, scattering from a CW-laser was detected and resolved over a large angular range ( from 12° to 168° and from 0° to 360°) from spherically shaped particles (e.g., amorphous silica and borosilicate glass) flowing through the reflector's focal plane at speeds of 20 to 30 m/s. The scattering pattern from individual particles flying through the focal plane of the ellipsoid mirror provides insights about a particle's size, clustering, roughness, and velocity.
As a byproduct of cellular metabolism, the emission of endogenous photons is a promising biomarker for physiological processes. However, direct biological applications are, so far, challenging because of the very low int...As a byproduct of cellular metabolism, the emission of endogenous photons is a promising biomarker for physiological processes. However, direct biological applications are, so far, challenging because of the very low intensity and the intrinsically non-stationary characteristics of this photon emission. Here, we outline and demonstrate the efficacy of a statistical procedure for reconstructing the real photon-number distributions from the photocounts provided by a single-photon detector. We develop a staged model-based regularized maximum-likelihood method capable of addressing this inverse problem in the few-photon regime. When applied to an ultra-low laser flux, the method recovers the expected Poisson statistics, whereas in the case of weak biophoton emission, the reconstruction of windowed counted photons reveals deviations from Poisson behavior in the unfolded photon-number distributions over time, underlying the typical non-stationary dynamics of biological emission.
Single-pixel imaging is a natural, secure imaging technique with a code of an imaging algorithm. To enhance security, in this paper, we propose a dual-mode SbSe PD (UV-responsive VIS-blind mode and UV-blind VIS-responsiv...Single-pixel imaging is a natural, secure imaging technique with a code of an imaging algorithm. To enhance security, in this paper, we propose a dual-mode SbSe PD (UV-responsive VIS-blind mode and UV-blind VIS-responsive mode), adding an additional code on the basis of single-pixel imaging. To realize the expected dual-mode, the structure of the PD is designed as Cu/Ag/TiO/SbSe/ITO/IGO. Thus, the PD on the ITO/IGO side realizes UV blind (254 nm: 4 × 10mA/W, 365 nm: 1.9 × 10mA/W, 395 nm: 6.83 × 10mA/W, white light: 429 mA/W under 0 V). On the other side, due to ZWB1's weak penetration ability of visible light, the PD realizes visible blindness (254 nm: 36 mA/W, 365 nm: 20 mA/W, 395 nm: 12 mA/W, white light: 3.5 × 10mA/W under 0 V). Then, we demonstrate secure single-pixel imaging with the proposed PD and single-pixel imaging. This work may bring an innovative approach to improve the security of cameras and extend the applications of single-pixel imaging and SbSe PDs.
Optical frequency combs combine ultrashort pulse duration and phase stability, making them powerful resources for high-precision ranging even when affected by atmospheric dispersion. It has been established that by class...Optical frequency combs combine ultrashort pulse duration and phase stability, making them powerful resources for high-precision ranging even when affected by atmospheric dispersion. It has been established that by classical modal engineering and mode-sensitive detection, sensitivity to distance at the standard limit can be achieved; however, attaining improved uncertainties by the use of squeezing has not been explored. Here, we apply an effective Hamiltonian framework to the problem of ranging with quantum frequency combs in order to derive the associated precision bounds for distance estimation. The problem needs addressing of the pulse shape and its quantum properties at once. The analysis reveals that quantum solutions may be appealing mostly for short-distance applications.
A single-mode sapphire photonic crystal fiber (S-PCF) fabricated via femtosecond laser direct writing is demonstrated, with a fiber Bragg grating inscribed in the core. A two-step cladding strategy is proposed: waveguide...A single-mode sapphire photonic crystal fiber (S-PCF) fabricated via femtosecond laser direct writing is demonstrated, with a fiber Bragg grating inscribed in the core. A two-step cladding strategy is proposed: waveguide arrays are written point-by-point along the fiber axis in a hexagonal lattice to form an artificial photonic crystal cladding. The lower half of the lattice is first inscribed, followed by embedding the FBG in the core and then completing the upper half to form a full PCF. This approach enables flexible geometry design, refractive index modulation, and precise modal control. Experiments show single-mode guidance under different lattice pitches, cladding layers, and index modulation. The fabricated sapphire PCF-FBG exhibits effective confinement with a near-Gaussian mode distribution, 0.20 nm bandwidth, 14.45 dB SNR, and a reflectivity of 48.5. It also demonstrates stable high-temperature performance from 20 to 1500 °C with enhanced temperature sensitivity.
Torsion pendulums offer exceptional torque sensitivity but inherently suffer from slow response times, limiting time-resolved measurements. We present a single-period, self-resetting optical torque sensor based on a silk...Torsion pendulums offer exceptional torque sensitivity but inherently suffer from slow response times, limiting time-resolved measurements. We present a single-period, self-resetting optical torque sensor based on a silk fiber torsion pendulum operating in ultra-high vacuum. This non-resonant, time-domain approach enables the detection of discrete optical torque pulses at the attonewton-meter level within seconds, without high quality factors or active damping. The pendulum's intrinsic mechanical relaxation provides a natural reset between measurements, allowing successive readings. We validate the method using radiation-pressure torque from a laser beam and demonstrate its practicality by measuring solar radiation pressure, providing a compact platform for dynamic optomechanical force sensing.
We propose parallel image-scanning autocorrelation-deconvolution microscopy (PISADM), a multifocal-scanning strategy that converts global reconstruction into spatially localized reconstructions. By combining spatially lo...We propose parallel image-scanning autocorrelation-deconvolution microscopy (PISADM), a multifocal-scanning strategy that converts global reconstruction into spatially localized reconstructions. By combining spatially localized multifocal excitation with scanning-position-wise SACD reconstruction and focus-wise pixel reassignment, PISADM reduces the effective accumulation of finite-frame cross terms and improves reconstruction stability in dense regions, thereby enhancing the separability of closely spaced structures. Monte-Carlo simulations show that, at an SBR of 10 dB, PISADM reduces the stable separability limit to approximately 100-110 nm, compared with about 140-150 nm for SACD under the same conditions. Fourier ring correlation analysis shows that PISADM preserves more reliable high-frequency information near the separability limit. In two-dimensional, long-term, and three-dimensional imaging of PCSTAR-labeled microtubules, PISADM consistently provides clearer separation of neighboring filaments while better preserving structural fidelity. These results indicate that PISADM provides a practical strategy for resolving densely packed structures with small spatial separations in super-resolution imaging.
We propose a deep-learning-based method for rapid meta-beam-splitter design that accounts for near-field coupling effects. This method combines beam-shaping optimization with a convolutional neural network that predicts...We propose a deep-learning-based method for rapid meta-beam-splitter design that accounts for near-field coupling effects. This method combines beam-shaping optimization with a convolutional neural network that predicts the coupling-aware complex near-field response from the meta-atom configuration. By encoding the meta-atoms using a differentiable image representation, the gradients can be backpropagated through the near-field response to the structural parameters, enabling fast gradient-based optimization. Using this method, we design a 1 × 5 meta-beam splitter in 24 s with 92.33% uniformity in simulation. These results highlight the potential of metasurfaces for optical communications, light detection and ranging, and other systems requiring precise beam control.
This work investigates the enhancement of channel capacity in photon-starved deep-space optical links by leveraging inter-photon correlations. We analyze an M-ary pulse-position modulation (PPM) photon-counting channel i...This work investigates the enhancement of channel capacity in photon-starved deep-space optical links by leveraging inter-photon correlations. We analyze an M-ary pulse-position modulation (PPM) photon-counting channel in the presence of Poisson background noise and compare conventional signal sources with recently proposed correlated photonic-dimer sources. In the low-photon-rate regime, the dimer sources in both the Bose-Einstein condensate (BEC) and Bardeen-Cooper-Schrieffer (BCS) limits yield substantial capacity improvements over conventional sources. Specifically, at the operationally relevant PPM order of = 128, the increase relative to lasers reaches up to ∼37% (BEC) and ∼94% (BCS), respectively. These results underscore photon-statistics and correlation engineering as a promising degree of freedom for maximizing photon information efficiency under stringent power and transceiver constraints.
We demonstrated a watt-level continuous-wave intracavity diamond Raman laser operating at 1634 nm in the eye-safe spectral region. By employing a dual Nd:YVO₄ crystal pumping configuration in combination with a Z‑shaped...We demonstrated a watt-level continuous-wave intracavity diamond Raman laser operating at 1634 nm in the eye-safe spectral region. By employing a dual Nd:YVO₄ crystal pumping configuration in combination with a Z‑shaped cavity design, the thermal lensing effect in the laser crystal was significantly suppressed. Consequently, the maximum injected pump power was increased from 40 W in a single-crystal scheme to 130 W, yielding 18.4 W of fundamental laser at 1342 nm. With the fundamental beam tightly focused to a 65 μm waist radius on the diamond, continuous-wave Raman output at 1634 nm was achieved with a power of 1.46 W, representing the highest power reported. The device also exhibits good beam quality (M < 1.3) and power stability (RMS < 2% over 1 hour). Numerical simulations further indicate that by increasing the local pump density within the Raman medium and optimizing the output coupling ratio, the output power can potentially be scaled to the 10 W level.