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. This result, as far as we are aware, represents the first instance of an all-fiber laser demonstration exceeding the kilowatt level in conjunction with GHz-level linewidths. It could serve as a benchmark for effectively managing spectral linewidth, minimizing stimulated Brillouin scattering, and controlling thermal management issues in high-power, narrow-linewidth fiber lasers.

A high-performance vector torsion sensor, designed using an in-fiber Mach-Zehnder interferometer (MZI), is proposed. The sensor includes a straight waveguide, which is inscribed within the core-cladding boundary of the standard single-mode fiber (SMF) by a single femtosecond laser inscription step. A 5-millimeter in-fiber MZI, fabricated in less than a minute, showcases rapid and efficient production. The device's asymmetric structure is correlated with a strong polarization dependence, as shown by the transmission spectrum's prominent polarization-dependent dip. Due to the varying polarization state of the input light in the in-fiber MZI caused by fiber twist, torsion sensing is achievable by observing the polarization-dependent dip. The dip's wavelength and intensity facilitate torsion demodulation, and vector torsion sensing is realized by configuring the polarization of the incident light accordingly. The intensity modulation method showcases a torsion sensitivity that reaches 576396 dB/(rad/mm). The strain and temperature's effect on dip intensity is quite minimal. The incorporated MZI design, situated within the fiber, keeps the fiber's coating intact, thereby sustaining the complete fiber's ruggedness.

This paper introduces, for the first time, a novel approach to safeguarding the privacy and security of 3D point cloud classification using an optical chaotic encryption scheme, addressing the prevalent issues of privacy and security in this domain. Acetohydroxamic in vitro Spin-polarized vertical-cavity surface-emitting lasers (MC-SPVCSELs) with mutual coupling, exposed to double optical feedback (DOF), are examined for generating optical chaos used in the encryption of 3D point clouds with permutation and diffusion. The nonlinear dynamics and complexity results conclusively indicate that MC-SPVCSELs with degrees of freedom have extremely high chaotic complexity, enabling an extraordinarily large key space. The ModelNet40 dataset's 40 object categories underwent encryption and decryption using the proposed scheme for all test sets, and the PointNet++ methodology recorded every classification result for the original, encrypted, and decrypted 3D point cloud data for all 40 categories. The encrypted point cloud's class accuracies are, unexpectedly, overwhelmingly zero percent, except for the plant class which demonstrates one million percent accuracy. This clearly shows the encrypted point cloud's lack of classifiable or identifiable attributes. There is a striking similarity between the accuracies of the decryption classes and those of the original classes. The classification findings thus validate the practical application and exceptional performance of the proposed privacy protection strategy. The encryption and decryption procedures, in summary, show that the encrypted point cloud images are unclear and unrecognizable, but the decrypted point cloud images are precisely the same as the original data. This paper's security analysis is enhanced by the examination of the geometric structures presented within 3D point cloud data. Subsequently, the security analysis demonstrates that the suggested privacy protection method exhibits a high security level and satisfactory privacy preservation for classifying 3D point clouds.

A sub-Tesla external magnetic field is predicted to generate the quantized photonic spin Hall effect (PSHE) in a system comprising strained graphene on a substrate, demonstrating a considerably smaller magnetic field requirement than that necessary for the effect to occur in typical graphene-substrate structures. Within the PSHE, distinct quantized patterns emerge in in-plane and transverse spin-dependent splittings, exhibiting a strong correlation with the reflection coefficients. Quantized photo-excited states (PSHE) in a standard graphene structure arise from the splitting of real Landau levels; however, in a strained graphene substrate, the quantized PSHE is due to the splitting of pseudo-Landau levels induced by pseudo-magnetic fields. This quantization is further impacted by the lifting of valley degeneracy in the n=0 pseudo-Landau levels, a direct result of applying sub-Tesla external magnetic fields. As the Fermi energy evolves, the pseudo-Brewster angles of the system are correspondingly quantized. The sub-Tesla external magnetic field and the PSHE display quantized peak values, situated near these angles. The giant quantized PSHE is predicted to be the tool of choice for direct optical measurements on the quantized conductivities and pseudo-Landau levels within the monolayer strained graphene.

Polarization-sensitive near-infrared (NIR) narrowband photodetection techniques are becoming increasingly important for applications in optical communication, environmental monitoring, and intelligent recognition systems. However, the current implementation of narrowband spectroscopy remains heavily dependent on additional filtering or a large-scale spectrometer, a characteristic that is detrimental to the pursuit of on-chip integration miniaturization. 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. This study demonstrates polarization-sensitive, narrowband infrared photodetection in graphene devices coupled with OTS, the design of which utilizes the finite-difference time-domain (FDTD) method. Devices display a narrowband response at NIR wavelengths, attributed to the tunable Tamm state's influence. At a full width at half maximum (FWHM) of 100nm, the response peak exhibits a characteristic broadening, potentially ameliorated to an ultra-narrow 10nm width through the enhancement of the dielectric distributed Bragg reflector (DBR) periods. The device's 1550nm operation yields a responsivity of 187 milliamperes per watt and a response time of 290 seconds. Acetohydroxamic in vitro Furthermore, the integration of gold metasurfaces yields prominent anisotropic features and high dichroic ratios of 46 at 1300nm and 25 at 1500nm.

Non-dispersive frequency comb spectroscopy (ND-FCS) forms the basis of a fast gas sensing technique that is both proposed and experimentally demonstrated. Through the application of time-division-multiplexing (TDM), the experimental assessment of its multi-component gas measurement capacity also involves the selective wavelength retrieval from the fiber laser 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). Dynamic monitoring, alongside long-term stability evaluation, is undertaken for ammonia (NH3), carbon monoxide (CO), and carbon dioxide (CO2). Human breath's rapid CO2 detection is also performed. Acetohydroxamic in vitro The detection limits, derived from experimental results using a 10 ms integration time, are 0.00048%, 0.01869%, and 0.00467% for the respective species. While a minimum detectable absorbance (MDA) of 2810-4 is achievable, a dynamic response with millisecond timing is possible. The ND-FCS sensor, which we have developed, displays remarkable gas sensing capabilities, including high sensitivity, swift response, and long-term stability. This technology presents noteworthy potential for tracking multiple gases within atmospheric environments.

Transparent Conducting Oxides (TCOs) demonstrate a significant, ultrafast alteration in refractive index within their Epsilon-Near-Zero (ENZ) spectral range, a behavior that is highly sensitive to both material properties and measurement configurations. Hence, the optimization of ENZ TCO's nonlinear response often entails a significant volume of nonlinear optical measurement procedures. Our analysis of the material's linear optical response indicates a method to circumvent considerable experimental endeavors. Material properties varying with thickness are accounted for in the analysis of absorption and field intensity enhancement under diverse measurement conditions, thereby estimating the incident angle necessary for a maximum nonlinear response in a specific TCO film. Nonlinear transmittance measurements, dependent on both angle and intensity, were performed on Indium-Zirconium Oxide (IZrO) thin films with differing thicknesses, demonstrating a satisfactory correlation between empirical findings and theoretical calculations. Our investigation reveals the potential for adjusting both film thickness and the angle of excitation incidence concurrently, yielding optimized nonlinear optical responses and enabling flexible design for highly nonlinear optical devices employing transparent conductive oxides.

For the realization of precision instruments, like the giant interferometers used for detecting gravitational waves, the measurement of very low reflection coefficients at anti-reflective coated interfaces is a significant concern. Utilizing low coherence interferometry and balanced detection, this paper details a method for obtaining the spectral dependency of the reflection coefficient's amplitude and phase, achieving a sensitivity of around 0.1 ppm and a spectral resolution of 0.2 nm. This approach also effectively eliminates any unwanted influence from the existence of uncoated interfaces. This method's data processing procedures bear a resemblance to those used in Fourier transform spectrometry. Formulas governing the accuracy and signal-to-noise ratio of this methodology having been established, we now present results that fully validate its successful operation across diverse experimental scenarios.