Stimulated transitions of erbium ions within the ErLN material bring about optical amplification, consequently effectively compensating for optical loss, meanwhile. Medicare savings program In theoretical analysis, bandwidth surpassing 170 GHz with a half-wave voltage of 3V has been successfully realized. Moreover, a forecast for the propagation compensation effectiveness is 4dB at 1531nm.
Within the framework of noncollinear acousto-optic tunable filter (AOTF) device construction and study, the refractive index plays a pivotal part. Previous studies, though they have considered the effects of anisotropic birefringence and rotatory properties, remain reliant on paraxial and elliptical approximations. These approximations can lead to notable errors exceeding 0.5% in the geometric parameters of TeO2 noncollinear AOTF devices. This paper tackles the approximations and their effects using refractive index correction as a means. For the design and implementation of noncollinear acousto-optic tunable filters, this essential theoretical research has noteworthy implications.
The Hanbury Brown-Twiss approach, focusing on the correlation of intensity fluctuations at two distinct points within a wave field, exposes the fundamental aspects of light. An imaging and phase recovery approach for dynamic scattering media is presented and experimentally demonstrated using the Hanbury Brown-Twiss technique. The theoretical underpinnings, thoroughly detailed, are supported by experimental validation. The proposed technique is validated by exploiting the temporal ergodicity of the dynamically scattered light's randomness to evaluate correlations between intensity fluctuations. This analysis is then utilized for reconstructing the object concealed by the dynamic diffuser.
Via spectral-coded illumination, we present in this letter, to the best of our knowledge, a novel scanning-based compressive hyperspectral imaging approach. Efficient and adaptable spectral modulation is achieved through spectral coding applied to a dispersive light source. Point-wise scanning captures spatial data, applicable to optical scanning imaging systems such as lidar. In conjunction with previous works, we propose a new tensor-based hyperspectral image reconstruction algorithm. This algorithm considers both spectral correlation and spatial self-similarity for the reconstruction of three-dimensional hyperspectral data from compressive measurements. Experimental results from both simulated and real scenarios highlight our method's superior visual quality and quantitative analysis.
The adoption of diffraction-based overlay (DBO) metrology has been instrumental in addressing the increasing need for tighter overlay control in cutting-edge semiconductor production. Moreover, the accuracy and reliability of DBO metrology often depend on utilizing multiple wavelengths to compensate for target distortions. The present letter outlines a multi-spectral DBO metrology proposal centered on the linear dependence of overlay errors on the combinations of off-diagonal-block Mueller matrix elements, (Mij – (-1)^jMji) with i = 1, 2 and j = 3, 4, specific to the zeroth-order diffraction of overlay target gratings. medical check-ups We introduce a method capable of capturing snapshots and directly measuring M within a broad spectral range, free from the use of rotating or active polarization components. A single shot is sufficient to demonstrate the proposed method's capability for multi-spectral overlay metrology, according to the simulation results.
We determine the relationship between the ultraviolet (UV) pump wavelength and the visible laser performance of Tb3+LiLuF3 (TbLLF), revealing the initial design of a UV-laser-diode-pumped Tb3+-based laser. In UV pump wavelengths that have a strong excited-state absorption (ESA), thermal effects begin to appear at moderate pump powers, but this effect disappears at wavelengths with a weaker excited-state absorption. In a 3-mm short Tb3+(28 at.%)LLF crystal, continuous wave laser operation is made possible by a UV laser diode that emits at 3785nm. Slope efficiencies of 36% at 542/544 nanometers and 17% at 587 nanometers are accomplished by a minimum laser threshold of 4 milliwatts.
We experimentally proved the efficacy of polarization multiplexing schemes, implemented within tilted fiber gratings (TFBGs), to yield polarization-independent fiber optic surface plasmon resonance (SPR) sensors. Employing two orthogonally polarized light sources, separated by a polarization beam splitter (PBS), both p-polarized and precisely aligned with the tilted grating plane within polarization-maintaining fiber (PMF), facilitates the transmission of p-polarized light in opposing directions through the Au-coated TFBG, thus inducing Surface Plasmon Resonance (SPR). Polarization multiplexing was further realized via the examination of two polarization components and the subsequent utilization of a Faraday rotator mirror (FRM) for the SPR effect. Despite variations in light source polarization or fiber perturbations, the SPR reflection spectra remain polarization-independent, resulting from the equal integration of p- and s-polarized transmission spectra. MGL-3196 clinical trial Spectrum optimization is employed to diminish the presence of the s-polarization component, as detailed. This TFBG-based SPR refractive index (RI) sensor, impervious to polarization changes caused by mechanical disturbances, boasts a remarkable wavelength sensitivity of 55514 nm/RIU and an amplitude sensitivity of 172492 dB/RIU for small changes.
The potential of micro-spectrometers is substantial in diverse areas, encompassing medicine, agriculture, and aerospace applications. We propose a QD (quantum-dot) light-chip micro-spectrometer in this work, in which QDs emit distinct wavelengths, ultimately processed with a spectral reconstruction (SR) algorithm. The QD array's dual functionality encompasses both the role of a light source and that of a wavelength division structure. Sample spectra are obtained through the utilization of this simple light source, a detector, and an algorithm, resulting in a spectral resolution of 97nm within the wavelength spectrum spanning from 580nm to 720nm. A 475 mm2 area defines the QD light chip, a remarkable 20 times smaller than the halogen light sources employed in commercial spectrometers. A wavelength division structure is dispensable, resulting in a much smaller spectrometer volume. Material identification using a micro-spectrometer was showcased effectively. Three kinds of transparent samples—genuine and imitation leaves, plus real and fake blood—attained 100% classification accuracy in the demonstration. These results on the QD light chip-based spectrometer suggest its capability for a wide range of future applications.
Applications such as optical communication, microwave photonics, and nonlinear optics benefit from the promising integration platform of lithium niobate-on-insulator (LNOI). Low-loss fiber-chip coupling is essential for realizing the potential of lithium niobate (LN) photonic integrated circuits (PICs). We experimentally validate and propose, within this letter, a silicon nitride (SiN) assisted tri-layer edge coupler on an LNOI platform. The edge coupler's design incorporates a bilayer LN taper and an interlayer coupling structure, comprising an 80 nm-thick SiN waveguide and an LN strip waveguide. Measurements at 1550 nm reveal a fiber-chip coupling loss of 0.75 dB/facet for the TE mode. The waveguide transition from silicon nitride to lithium niobate strip waveguide exhibits a loss of 0.15 decibels. The precision of the fabrication tolerance is high for the SiN waveguide in the tri-layer edge coupler.
The extreme miniaturization of imaging components, achieved by multimode fiber endoscopes, facilitates minimally invasive deep tissue imaging. Fiber optic systems, in their typical configuration, are frequently hampered by limited spatial resolution and lengthy measurement durations. Utilizing computational optimization algorithms with hand-picked priors, fast super-resolution imaging through a multimode fiber has been successfully executed. In contrast, machine learning reconstruction approaches promise superior prior models, yet necessitate extensive training datasets, consequently leading to excessively long and impractical pre-calibration periods. An unsupervised learning approach with untrained neural networks is utilized to develop a method for multimode fiber imaging, which we report here. By dispensing with pre-training, the proposed approach effectively tackles the ill-posed inverse problem. Untrained neural networks have been shown, both theoretically and experimentally, to enhance the imaging quality and provide sub-diffraction spatial resolution within multimode fiber imaging systems.
Our approach, a deep learning-based reconstruction framework for fluorescence diffuse optical tomography (FDOT), achieves high accuracy by addressing the problem of background mismodeling. The formulation of a learnable regularizer incorporating background mismodeling takes the form of particular mathematical constraints. A physics-informed deep network is implicitly utilized to automatically learn the background mismodeling for the subsequent training of the regularizer. A deep and unfurled FIST-Net, uniquely crafted for optimizing L1-FDOT, aims to decrease the total number of learnable parameters. Through experimentation, a noticeable improvement in FDOT's accuracy is observed, facilitated by the implicit learning process of background mismodeling, thus substantiating the validity of deep background-mismodeling-learned reconstruction. The proposed framework provides a general solution for enhancing a class of image modalities that rely on linear inverse problems, explicitly acknowledging the presence of unknown background modeling errors.
Forward-scattering image recovery has benefited from the application of incoherent modulation instability, but the analogous method for backscatter image retrieval remains subpar. Within this paper, a polarization-modulation-driven, instability-based nonlinear imaging method is proposed, considering the preservation of polarization and coherence in 180-degree backscatter. A coupling model, based on Mueller calculus and the mutual coherence function, is developed to analyze both instability generation and image reconstruction.