From the synthesis of confined-doped fiber, near-rectangular spectral injection, and a 915 nm pump mechanism, a 1007 W signal laser with a 128 GHz linewidth is produced. Based on our current understanding, this outcome is the first to demonstrate all-fiber lasers surpassing the kilowatt-level with GHz-level linewidths. This achievement offers a pertinent reference for managing spectral linewidth alongside reducing stimulated Brillouin scattering and thermal management challenges in high-power, narrow-linewidth fiber lasers.

We outline a high-performance vector torsion sensor that relies on an in-fiber Mach-Zehnder interferometer (MZI). The sensor consists of a straight waveguide embedded precisely within the core-cladding boundary of the SMF, accomplished through a single femtosecond laser inscription procedure. A one-minute fabrication process yields a 5-millimeter in-fiber MZI. The transmission spectrum displays a substantial polarization-dependent dip, highlighting the polarization dependence stemming from the device's asymmetric structure. Fiber twist influences the polarization state of the input light in the in-fiber MZI, enabling torsion detection via observation of the polarization-dependent dip. Torsion, measurable through both the wavelength and intensity characteristics of the dip, is demodulated, and vector torsion sensing is attainable through the appropriate incident light polarization. Intensity modulation yields a torsion sensitivity of 576396 dB per radian per millimeter. Strain and temperature have a weak impact on the magnitude of the dip intensity. In addition, the fiber-integrated MZI structure safeguards the fiber's coating, thus preserving the overall robustness of the fiber.

In this paper, a novel privacy protection method for 3D point cloud classification is introduced, based on an optical chaotic encryption scheme. For the first time, this method is implemented, specifically addressing the issues of privacy and security. this website Double optical feedback (DOF) is applied to mutually coupled spin-polarized vertical-cavity surface-emitting lasers (MC-SPVCSELs) to investigate optical chaos for encrypting 3D point clouds via permutation and diffusion processes. Nonlinear dynamics and complexity results affirm that MC-SPVCSELs equipped with degrees of freedom possess high chaotic complexity and can generate a tremendously large key space. The ModelNet40 dataset, with its 40 object categories, underwent encryption and decryption using the proposed method for all its test sets, and the PointNet++ analyzed and listed the complete classification results for the original, encrypted, and decrypted 3D point clouds for each of the 40 categories. Intriguingly, the encrypted point cloud's class accuracies exhibit nearly uniform zero percent values, with the notable exception of the plant class, achieving a phenomenal one million percent. This outcome signifies the encrypted point cloud's unclassifiable and unidentified nature. There is a striking similarity between the accuracies of the decryption classes and those of the original classes. Accordingly, the classification outcomes affirm the practical feasibility and exceptional effectiveness of the suggested privacy safeguard mechanism. The encryption and decryption processes, ultimately, highlight the ambiguity and unidentifiability of the encrypted point cloud imagery, with the decrypted point cloud imagery perfectly mirroring the initial images. Moreover, the security assessment of this paper is improved through the analysis of the geometrical aspects of 3D point clouds. The privacy protection scheme, when subjected to thorough security analyses, consistently shows high security and excellent privacy preservation for the 3D point cloud classification process.

The prediction of a quantized photonic spin Hall effect (PSHE) in a strained graphene-substrate system hinges on a sub-Tesla external magnetic field, presenting a significantly less demanding magnetic field strength in comparison to the conventional graphene-substrate system. In the PSHE, a distinctive difference in quantized behaviors is found between in-plane and transverse spin-dependent splittings, closely tied to reflection coefficients. While quantized photo-excited states (PSHE) in a standard graphene platform are a product of real Landau level splitting, the equivalent phenomenon in a strained graphene substrate is linked to pseudo-Landau level splitting, which is further complicated by the pseudo-magnetic field's influence. This pseudo-Landau level splitting is complemented by the lifting of valley degeneracy in the n=0 pseudo-Landau levels, a result of sub-Tesla external magnetic fields. Modifications to the Fermi energy correspondingly impact the quantized nature of the system's pseudo-Brewster angles. These angles mark the locations where the sub-Tesla external magnetic field and the PSHE display quantized peak values. The giant quantized PSHE is foreseen to enable direct optical measurements of quantized conductivities and pseudo-Landau levels in the monolayer strained graphene.

Optical communication, environmental monitoring, and intelligent recognition systems have all benefited from the significant interest in polarization-sensitive narrowband photodetection in the near-infrared (NIR) spectrum. The current narrowband spectroscopy method, however, is largely reliant on added filters or bulky spectrometers, which is contrary to the goal of achieving miniaturization within on-chip integration. Recently, topological phenomena, exemplified by the optical Tamm state (OTS), have offered a novel avenue for crafting functional photodetection devices, and we have, to the best of our knowledge, experimentally realized a device based on a 2D material (graphene) for the first time. In OTS-coupled graphene devices, designed through the finite-difference time-domain (FDTD) method, we showcase polarization-sensitive narrowband infrared photodetection. Due to the tunable Tamm state, the devices demonstrate a narrowband response specific to NIR wavelengths. A full width at half maximum (FWHM) of 100nm is observed in the response peak, a possibility for an ultra-narrow FWHM of approximately 10nm exists, contingent upon increasing the periods of the dielectric distributed Bragg reflector (DBR). The device's responsivity at 1550nm is 187mA/W; its response time is 290 seconds. this website Achieving prominent anisotropic features and high dichroic ratios, 46 at 1300nm and 25 at 1500nm, hinges on the integration of gold metasurfaces.

A method for rapid gas sensing is proposed and demonstrated experimentally, using non-dispersive frequency comb spectroscopy (ND-FCS) as the underlying technology. Its capability to measure multiple components of gas is experimentally examined, utilizing a time-division-multiplexing (TDM) strategy to isolate particular wavelengths of the fiber laser's optical frequency comb (OFC). A dual-channel optical fiber sensing methodology is implemented, featuring a multi-pass gas cell (MPGC) as the sensing path and a reference channel for calibrated signal comparison. This enables real-time stabilization and lock-in compensation for the optical fiber cavity (OFC). We conduct long-term stability evaluation and simultaneous dynamic monitoring of the target gases ammonia (NH3), carbon monoxide (CO), and carbon dioxide (CO2). The detection of fast CO2 in human breath is also carried out. this website Evaluated at an integration time of 10 milliseconds, the three species' detection limits were determined to be 0.00048%, 0.01869%, and 0.00467%, respectively, based on the experimental results. A minimum detectable absorbance (MDA) of 2810-4, which enables a dynamic response occurring within milliseconds, is attainable. Our innovative ND-FCS demonstrates significant gas-sensing advantages: high sensitivity, prompt response, and exceptional long-term stability. The application of this technology to atmospheric monitoring of various gases holds great potential.

The Epsilon-Near-Zero (ENZ) refractive index of Transparent Conducting Oxides (TCOs) demonstrates an enormous and super-fast intensity dependency, a characteristic profoundly determined by the material's properties and the particular measurement setup. Consequently, optimizing the nonlinear behavior of ENZ TCOs frequently necessitates a substantial investment in nonlinear optical measurements. This investigation reveals that a comprehensive analysis of the material's linear optical response can obviate the necessity for extensive experimental procedures. The impact of thickness-varying material properties on absorption and field strength augmentation, as analyzed, considers different measurement setups, and determines the optimal incident angle for maximum nonlinear response in a given TCO film. The angle- and intensity-dependent nonlinear transmittance of Indium-Zirconium Oxide (IZrO) thin films, varying in thickness, were evaluated experimentally, demonstrating a good accordance with the theoretical framework. The optimization of nonlinear optical response through the simultaneous adjustment of film thickness and excitation angle of incidence permits the flexible design of TCO-based high-nonlinearity optical devices, as indicated by our results.

The need to measure very low reflection coefficients of anti-reflective coated interfaces has become a significant factor in creating precision instruments, including the enormous interferometers dedicated to the detection of gravitational waves. This paper introduces a method, leveraging low coherence interferometry and balanced detection, enabling the determination of the spectral dependence of the reflection coefficient's amplitude and phase with a sensitivity of approximately 0.1 ppm and a spectral resolution of 0.2 nm. Furthermore, the method mitigates any spurious effects stemming from uncoated interfaces. Data processing, akin to Fourier transform spectrometry, is also a part of this method. The formulas governing precision and signal-to-noise have been established, and the results presented fully demonstrate the success of this methodology across a spectrum of experimental settings.