The interaction between light and vapors in the presence of magnetic fields is fundamental to many quantum technologies and applications. Recently, the ability to geometrically confine atoms into periodic structures has enabled the creation of chip-scale, micromachined hybrid atomic-diffractive optical elements. However, applying magnetic fields to such structures remains largely unexplored, offering potential for both fundamental and applied insights. Here, we present measurements of an atomic-diffractive optical element subject to magnetic fields. In contrast to the well-known polarization rotation in a Faraday medium, these diffractive atomic elements exhibit additional, rapidly oscillating rotation terms, which we validate both theoretically and experimentally. Moreover, we find that the introduction of spatially varying magnetic fields leads to a reduction in fringe visibility, which can be leveraged for gradiometric applications. Together, these effects establish a chip-scale platform where diffraction and quantum sensing are inseparably co-engineered, unveiling previously inaccessible regimes of atom–photon–magnetic interaction. By probing the magneto-optic response of periodically confined vapors, our results lay the groundwork for integrated smart-cell magnetometers and open new avenues for flat-optics-enabled quantum photonic devices.

Recent advances in single-photon detectors have enabled low-light detection in diverse applications ranging from biological imaging to astronomy. However, it remains a challenge to realizing high-quality optical imaging through dynamic and complex scattering media under photon-limited conditions. In this paper, we report high-quality photon-limited imaging through dynamic and complex scattering media using a single-photon detector. To eliminate a series of dynamic scaling factors induced by complex scattering in dynamic media, an iterative algorithm is developed to retrieve an estimated object image and a series of corrected measurements, revealing a correlation relationship between the illumination patterns and corrected measurements. Then, the estimated object image and corrected measurements are fed to an untrained neural network powered by regularization with denoising for quality enhancement. Experimental results demonstrate that the proposed method can be applied to implement high-quality photon-limited imaging through complex scattering media at low-light levels. This work opens up an avenue for exploring photon-limited imaging in challenging environments with a single-photon detector.

In this work, we exploit two third-order nonlinear effects, stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS), within an optical cavity for Brillouin vortex beam generation, using diamond as the nonlinear medium. The SRS process is employed to generate a first-order Stokes field, which serves as an intermediate pump to drive the generation of SBS in diamond. A theoretical model is developed to illustrate how variations in cavity length can be used to manipulate the transverse mode profiles of the diamond Brillouin fields under this indirect pumping scheme. Experimentally, by precisely tuning the diamond cavity length, we achieve Brillouin laser emission at ∼1240 nm, with output modes including both the fundamental Gaussian mode and Hermite–Gaussian modes with transverse orders ranging from 1 to 9. Furthermore, by implementing an extra-cavity astigmatic mode converter, we generate free-space diamond Brillouin vortex beams with topological charges from 1 to 4. These beams exhibit linewidths of 4.5–4.9 kHz, corresponding to a linewidth compression factor greater than 1.3 relative to the fundamental frequency. To the best of our knowledge, this is the first demonstration of free-space high-order Brillouin vortex beam generation, offering a new pathway for structured light generation in advanced optical systems.

Single-photon detectors with high detection rates are the foundation for the high-speed remote laser communication. Although a total detection rate of gigahertz has been achieved with multiple superconducting nanowires, the coupled single-mode fibers are incompatible with most large-aperture optical telescopes, and the uneven response distribution between nanowires also limits the system performance in practice. Here, we report a multimode fiber coupled superconducting nanowire single-photon detector (SNSPD) with a gigahertz detection rate through 16 intertwined niobium nitride nanowires operated at 2.4 K. The SNSPD is coupled with a 62.5 μm multimode fiber through beam compression. Overcoming the interference of speckles in multimode fibers, all nanowires perform highly uniform with narrow distributions of detection efficiencies (5.48% ± 0.136%), achieving a total detection efficiency of 87.6% and a total system detection efficiency of 52.3%, a maximum detection rate of 1.3 Gcps when the efficiency drops by 3 dB, and a highest detection rate of 3.1 Gcps before latching occurs. The significance of the uniform performance of pixels in terms of system speed is verified by modeling the combined detection rate vs the detection efficiency distribution, which is crucial in high-speed laser communication.

For on-chip optical power splitters, the ability to achieve arbitrary splitting-ratios holds potential significance, particularly in applications involving multi-wavelengths with different power ratios, such as χ(3) nonlinear effects. Here, we introduce a 2 × 2 power splitter on an AlGaAs-on-insulator (AlGaAsOI) platform. The proposed device is based on two 2 × 2 50/50 multimode interference (MMI) splitters connected by butterfly shaped waveguides that play the role of a phase shifter. By simply adjusting the length of the phase shifter, these double-MMI couplers can be configured to achieve any desired splitting ratio. The fabricated splitters show splitting ratios varying between 0/100 and 100/0 (at 1550 nm) with a low insertion loss of less than 0.4 dB. Furthermore, the 1-dB bandwidth of the devices is ∼120 nm. The experimental result aligns closely with our simulation, implying the robustness of the design and the fidelity of the fabrication. The demonstrated splitter/combiner will contribute to the high-level integration of AlGaAsOI nonlinear photonics integrated circuits but also open new opportunities for constructing novel-type nonlinear functional devices.

High power sources are desired in integrated photonics to utilize their full potential for various applications such as in telecom, medical, and remote sensing. However, the signal power from the integrated photonic sources has been quite limited. One of the main reasons for this is the usage of small optical mode area waveguides, which, although they help in keeping the footprint small and increasing the gain efficiency, limit the energy storage and extraction capability of the signal from an integrated device, thus limiting the output power. By increasing the optical mode area, one allows the photons to interact with a significantly larger number of gain ions, allowing large energy storage and power extraction. In light of this, we show a high-power continuous wave laser based on a recently demonstrated large-mode-area gain waveguide, which requires no external amplifier. The maximum power generated from the distributed Bragg reflector laser is close to 1.35 W with a slope efficiency of more than 50%, and it operates around the long wavelength window (∼1.85 μm) relevant for medical, space, and defense applications. The power level demonstrated here enables silicon photonics based continuous wave light sources comparable to their benchtop counterparts and brings them significantly closer to mass production and deployment for desired applications.

This study presents a broadband random Raman fiber laser (RRFL) with a threefold increase in wavelength coverage compared to single-wavelength pumping, along with flexible Raman gain manipulation. The system utilizes a half-open cavity configuration facilitated by a spectrally programmable multi-wavelength ytterbium-doped fiber laser as the pump source. Under single-wavelength pumping, the RRFL achieves an output wavelength range of 16 nm with a maximum output power of 4.77 W. By optimizing the pump parameters, including a wavelength spacing of 16 nm and a power ratio of ∼4:2:2, a three-wavelength pumping scheme enables multi-wavelength tunability over a range of 1102–1148 nm (46 nm, 10.9 THz), supporting outputs with two to five wavelengths. This work demonstrates an effective approach for enhancing broadband Raman transitions and advancing multi-wavelength RRFLs, with promising applications in sensing, communication systems, and precision spectroscopy.

In optical interferometric tomography (OIT), phase retrieval and alignment are crucial steps for achieving a precise measurement of the three-dimensional refractive index (3D RI) distribution within a sample. Traditionally, completing these two tasks requires multiple independent steps, each of which relies on extensive handcrafted prior knowledge, thereby constraining both the efficiency and precision of the measurements. To address this problem, we utilize deep learning techniques and propose a novel multi-task transformer network (MTTN) that can simultaneously retrieve the phase from single-frame interference patterns and align it with the scene center. We evaluate MTTN on both simulated and real-world data. The results demonstrate that MTTN achieves precise phase retrieval and alignment without additional prior knowledge. By integrating it with tomographic reconstruction techniques, we successfully reconstruct the 3D RI maps of micron-scale specialty optical fibers. We believe this framework provides a new technical solution for addressing challenges in OIT and related fields.

Nitrogen-vacancy (NV) centers in diamond are a promising platform for high-precision magnetometry. In contrast to the use of spontaneous emission in a number of NV-magnetometers, laser threshold magnetometry exploits stimulated emission of NV centers by placing an NV-doped diamond inside an optical cavity. The NV laser system is predicted to reach a high magnetic-field-dependent contrast and coherent signal strength, leading to an improved magnetic field sensitivity combined with high linearity. Here, we consider a two-media setup where the cavity additionally includes a vertical external cavity surface emitting a laser. This optically active material compensates cavity losses at 750 nm while still allowing for magnetic-field-dependent effects from the NV-diamond. We demonstrate a magnetic-field-dependent laser threshold and investigate the effects of pump laser induced absorption of the diamond. The experimental data are supported by an analytical simulation based on a rate model. Furthermore, we derive a generalized formula to compute the shot-noise-limited magnetic field sensitivity in the regime of high contrast, yielding 49.07(0.33)pT/Hz for the present setup. Simulations with an optimized NV-diamond suggest that values down to 4.9fT/Hz are possible.

Zirconium telluride (ZrTe2), a three-dimensional Dirac semimetal, combines high carrier mobility with robust environmental and structural stability, making it a suitable material for terahertz (THz) optoelectronics. Here, we report a ZrTe2-based rectenna that integrates broadband THz rectification and heterodyne mixing in a single device. The rectenna exhibits a peak responsivity of 800 V/W over the 0.02–0.32 THz range under 175 mV bias, with an ultrafast response time of 415 ns. Furthermore, it supports higher-order subharmonic mixing up to the 7th order, achieving a 10 dB intermediate frequency bandwidth exceeding 14 GHz. These results underscore the potential of ZrTe2 for compact, high-speed, and nonlinear THz signal detection and processing, with promising implications for next-generation wireless communication and sensing technologies.