To minimize measurement error, a strategy for selecting the optimal mode combination exhibiting the least error is presented and validated through both simulation and experimental results. Employing three distinct mode combinations for temperature and strain sensing, the optimal mode pairing, R018 and TR229, resulted in the lowest temperature and strain errors, measured at 0.12°C/39. Unlike sensors employing backward Brillouin scattering (BBS), the proposed scheme only necessitates frequency measurements centered around 1 GHz, leading to cost-effectiveness without the need for a high-frequency 10 GHz microwave source. There is a corresponding enhancement in accuracy as the FBS resonance frequency and spectrum linewidth are significantly smaller than those in the BBS.
Microscopy employing the quantitative differential phase-contrast (DPC) technique generates phase images of transparent samples, using a series of intensity images as input. Phase reconstruction in DPC microscopy, using a linearized model for weakly scattering objects, has limitations on the range of objects that can be imaged and demands additional measurements and sophisticated algorithms to counteract the system's aberrations. We present a DPC microscope with self-calibration, leveraging an untrained neural network (UNN) and a nonlinear image formation model. By employing our method, image restrictions are eliminated, and the intricate details and imperfections of the object are simultaneously reconstructed, without relying on any training data. Experiments using LED microscopes, together with numerical simulations, demonstrate the effectiveness of the UNN-DPC microscopy technique.
A robust all-fiber scheme employing femtosecond laser inscription of fiber Bragg gratings (FBGs) in a cladding-pumped seven-core Yb-doped fiber achieves efficient (70%) 1064-nm lasing, with a power output of 33W, exhibiting negligible differences between uncoupled and coupled cores. Although decoupled, the output spectrum differs substantially; seven separate lines, each corresponding to the reflection spectra from individual in-core FBGs, sum to a wide (0.22 nm) total spectrum; conversely, strong coupling results in the multiline spectrum's consolidation into a single, narrow spectral line. The modeled coupled-core laser demonstrates coherent superposition of supermodes, with their wavelength determined by the geometric mean of the individual FBG spectra. The resultant laser line displays broadening, its power broadening mirroring that of a single-core mode in an effective area seven times larger (0.004-0.012 nm).
The intricate capillary network presents a challenge for accurately measuring blood flow velocity, due to the small vessel dimensions and the slow movement of red blood cells (RBCs). In this study, we develop an optical coherence tomography (OCT) approach utilizing autocorrelation analysis to expedite the measurement of axial blood flow velocity within the capillary network. The axial blood flow velocity was derived from the phase shift within the decorrelation time of the first-order field autocorrelation function (g1) of OCT field data captured using the M-mode method of repeated A-scans. Subglacial microbiome The rotation center of g1 in the complex plane was initially set to the origin. Then, during the g1 decorrelation period, which generally lasts between 02 and 05 milliseconds, the phase shift caused by the movement of red blood cells (RBCs) was determined. The axial speed measurement, as indicated by phantom experiments, suggests the proposed method's accuracy within a wide range of 0.5 to 15 mm/s. Subsequent investigations of the method included trials with living animals. In contrast to phase-resolved Doppler optical coherence tomography (pr-DOCT), the proposed technique yields robust axial velocity measurements, achieving acquisition times more than five times faster.
The scattering of single photons in a phonon-photon hybrid system is studied using the waveguide quantum electrodynamics (QED) methodology. We examine the interaction of an artificial giant atom, cloaked in phonons within a surface acoustic wave resonator, with a coupled resonator waveguide (CRW) which is nonlocal via two connecting sites. Phonon-mediated transport of photons within the waveguide is controlled by the interference effect of nonlocal coupling. The magnitude of the coupling force between the giant atom and the surface acoustic wave resonator influences the width of the transmission valley or window in the near-resonant region. However, the two reflective peaks, stemming from Rabi splitting, converge into a single peak if the giant atom is significantly detuned from the surface acoustic resonator, which implies the existence of an effective dispersive coupling. The hybrid system's potential benefits from giant atoms are furthered by our study.
Extensive study and application of various optical analog differentiation methods have been undertaken in the field of edge-based image processing. We demonstrate a topological optical differentiation strategy that utilizes complex amplitude filtering, including amplitude and spiral phase modulation, within Fourier space. Theoretical and experimental demonstrations of isotropic and anisotropic multiple-order differentiation operations are presented. In the meantime, multiline edge detection is achieved, adhering to the differential order of the amplitude and phase objects. This proof-of-concept work promises to unlock new avenues for designing a nanophotonic differentiator and consequently constructing a more compact image processing apparatus.
The nonlinear (depleted) modulation instability regime of dispersion oscillating fibers exhibits parametric gain band distortion, as observed. Our analysis reveals that peak gain migration extends beyond the confines of the linear parametric gain band. Experimental observations find numerical simulation support.
We analyze the secondary radiation generated from orthogonal linearly polarized extreme ultraviolet (XUV) and infrared (IR) pulses, particularly its spectral properties within the second XUV harmonic region. By employing a polarization-filtering method, the two spectrally overlapping and competing channels—the XUV second-harmonic generation (SHG) process by an IR-dressed atom and the XUV-assisted recombination channel of high-order harmonic generation in the IR field—are separated [Phys. .]. Rev. A98, 063433 (2018)101103, a Phys. Rev. A article [PhysRevA.98063433], introduces a groundbreaking new method. Berzosertib in vitro The separated XUV SHG channel is utilized for accurate waveform retrieval of the IR pulse, allowing us to ascertain the range of applicable IR-pulse intensities.
One crucial approach in developing organic photodiodes with a broad spectral response (BS-OPDs) is the implementation of a photosensitive donor/acceptor planar heterojunction (DA-PHJ) as the active layer, which exhibits complementary light absorption. For achieving superior optoelectronic performance, the thickness ratio of the donor layer to the acceptor layer (DA thickness ratio) needs careful consideration, alongside the optoelectronic properties inherent in the DA-PHJ materials. NK cell biology We conducted an investigation into the effect of the DA thickness ratio on the performance of a BS-OPD, featuring tin(II) phthalocyanine (SnPc)/34,910-perylenetetracarboxylic dianhydride (PTCDA) as the active layer. Results indicated a substantial impact of the DA thickness ratio on device performance, leading to the identification of 3020 as the optimal thickness ratio for peak performance. Averaging across various trials, optimizing the DA thickness ratio yielded a 187% boost in photoresponsivity and a 144% increase in specific detectivity. The performance enhancement achieved at the optimized donor-acceptor (DA) thickness ratio is rooted in the elimination of traps, which enables efficient space-charge-limited photocarrier transport, and a balanced optical absorption spectrum across the entire wavelength range. The findings provide a strong photophysical basis for enhancing the efficiency of BS-OPDs through optimized thickness ratios.
In a groundbreaking experiment, we demonstrated, for the first time, that free-space optical transmission using polarization- and mode-division multiplexing is capable of high capacity and enduring significant atmospheric turbulence. To simulate strong turbulent optical links, a compact spatial light modulator-based polarization multiplexing multi-plane light conversion module was put into operation. A mode-division multiplexing system displayed a considerable improvement in turbulence resistance by using a multiple-input multiple-output decoder employing successive interference cancellation and incorporating redundant receiving channels. The single-wavelength mode-division multiplexing system, operating in a highly turbulent medium, demonstrated exceptional performance by achieving an unprecedented line rate of 6892 Gbit/s, incorporating ten channels and a net spectral efficiency of 139 bit/(s Hz).
An innovative approach is used to create a ZnO-based light-emitting diode (LED) that emits no light in the blue spectrum (blue-free). The Au/i-ZnO/n-GaN metal-insulator-semiconductor (MIS) structure now incorporates, for the first time as far as we are aware, a natural oxide interface layer, exhibiting significant potential for visible light emission. The unique interface between the Au, i-ZnO, and n-GaN materials effectively eliminated the undesirable blue emissions (400-500 nm) from the ZnO film, and the remarkable orange electroluminescence is primarily due to the impact ionization of the natural interface layer when subjected to a high electric field. The device's significant feature lies in its capability to achieve an ultra-low color temperature (2101 K) and excellent color rendering (928) under electrical injection. This demonstrates its suitability for use in electronic display applications and general illumination, and perhaps its unexpected utility in specialized lighting areas. The results, obtained through a novel and effective strategy, pave the way for the design and preparation of ZnO-related LEDs.
A proposed method and device for classifying the origin of Baishao (Radix Paeoniae Alba) slices rapidly, employing auto-focus laser-induced breakdown spectroscopy (LIBS), are presented in this communication.