The device's performance characteristics at 1550nm include a responsivity of 187mA/W and a response time of 290 seconds. Integration of gold metasurfaces is responsible for the prominent anisotropic features and the high dichroic ratios, which reach 46 at 1300nm and 25 at 1500nm.

A fast gas sensing strategy grounded in non-dispersive frequency comb spectroscopy (ND-FCS) is presented, along with its experimental validation. The experimental examination of its capability to measure multiple gas components is conducted using the time-division-multiplexing (TDM) technique, which precisely targets wavelength selection from the fiber laser optical frequency comb (OFC). The optical fiber channel (OFC) repetition frequency drift is monitored and compensated in real-time using a dual-channel fiber optic sensing scheme. This scheme incorporates a multi-pass gas cell (MPGC) as the sensing element and a calibrated reference path for tracking the drift. The target gases ammonia (NH3), carbon monoxide (CO), and carbon dioxide (CO2) are used for both long-term stability evaluation and simultaneous dynamic monitoring. Fast CO2 detection in exhaled human breath is also implemented. Based on the experimental integration time of 10 milliseconds, the detection limits of the three species are: 0.00048%, 0.01869%, and 0.00467%. Achieving a low minimum detectable absorbance (MDA) of 2810-4 is possible, coupled with a rapid, millisecond dynamic response. The ND-FCS sensor, which we have developed, displays remarkable gas sensing capabilities, including high sensitivity, swift response, and long-term stability. Its potential for measuring multiple gaseous components in atmospheric settings is substantial.

Transparent Conducting Oxides (TCOs) display an impressive, super-fast intensity dependence in their refractive index within the Epsilon-Near-Zero (ENZ) range, a variation directly correlated to the materials' properties and measurement conditions. Consequently, optimizing the nonlinear behavior of ENZ TCOs frequently necessitates a substantial investment in nonlinear optical measurements. This work highlights how an analysis of the material's linear optical response can substantially reduce the need for experimental procedures. The analysis assesses how thickness-dependent material parameters affect absorption and field strength augmentation under different measurement conditions, and calculates the incident angle needed to maximize the nonlinear response for a given TCO film. We meticulously measured the angle- and intensity-dependent nonlinear transmittance of Indium-Zirconium Oxide (IZrO) thin films, exhibiting diverse thicknesses, and found compelling agreement between our experiments and the theoretical model. 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.

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. A method, founded on low coherence interferometry and balanced detection, is put forward in this paper. This method not only allows for the determination of the spectral variation of the reflection coefficient in both amplitude and phase, with a sensitivity on the order of 0.1 ppm and a spectral resolution of 0.2 nm, but also eliminates potential unwanted effects from uncoated interfaces. selleckchem Data processing, akin to Fourier transform spectrometry, is also a part of this method. Having established the formulas governing accuracy and signal-to-noise ratio for this method, we now present results showcasing its successful operation across diverse experimental settings.

Our approach involved developing a hybrid sensor employing a fiber-tip microcantilever, featuring both fiber Bragg grating (FBG) and Fabry-Perot interferometer (FPI) components, enabling simultaneous temperature and humidity sensing. The FPI's polymer microcantilever, integrated onto the end of a single-mode fiber, was generated via femtosecond (fs) laser-induced two-photon polymerization. This approach resulted in a humidity sensitivity of 0.348 nm/%RH (40% to 90% relative humidity, at 25°C), and a temperature sensitivity of -0.356 nm/°C (25°C to 70°C, at 40% relative humidity). Laser micromachining with fs laser technology was used to etch the FBG's design onto the fiber core, line by line, demonstrating a temperature sensitivity of 0.012 nm/°C within the range of 25 to 70 °C and 40% relative humidity. Due to the FBG's exclusive temperature sensitivity in reflection spectra peak shifts, rather than humidity, the ambient temperature can be measured directly. The output from FBG sensors can be effectively incorporated into a temperature compensation strategy for FPI-based humidity detection systems. Therefore, the measured relative humidity is disassociated from the overall displacement of the FPI-dip, allowing the simultaneous determination of humidity and temperature values. This all-fiber sensing probe, boasting high sensitivity, a compact form factor, simple packaging, and dual-parameter measurement capabilities, is expected to be a crucial component in diverse applications requiring concurrent temperature and humidity readings.

We present a novel ultra-wideband photonic compressive receiver utilizing random code shifting to differentiate image frequencies. Randomly selected code center frequencies are altered over a substantial frequency range, thereby enabling a flexible increase in the receiving bandwidth. Simultaneously, there is a small variation in the central frequencies of two randomly chosen codes. To differentiate the accurate RF signal from the image-frequency signal, which has a different location, this difference is leveraged. Leveraging this principle, our system efficiently resolves the constraint of limited receiving bandwidth inherent in current photonic compressive receivers. Two 780-MHz output channels enabled the demonstration of sensing capabilities spanning the 11-41 GHz range in the experiments. A linear frequency modulated (LFM) signal, a quadrature phase-shift keying (QPSK) signal, and a single-tone signal, forming a multi-tone spectrum and a sparse radar communication spectrum, have been recovered.

Structured illumination microscopy (SIM), a popular super-resolution imaging approach, permits resolution improvements of two-fold or greater in accordance with the illumination patterns used. In the conventional method, linear SIM reconstruction is used to rebuild images. selleckchem This algorithm, unfortunately, incorporates hand-tuned parameters, which may result in artifacts, and it's unsuitable for utilization with sophisticated illumination patterns. Deep neural networks are now part of SIM reconstruction procedures, however, suitable training datasets, obtained through experimental means, remain elusive. The deep neural network, in conjunction with the structured illumination process's forward model, enables us to reconstruct sub-diffraction images without prior training. By optimizing on a single set of diffraction-limited sub-images, the resulting physics-informed neural network (PINN) circumvents the necessity of any training set. Through both simulation and experimentation, we show that this PINN approach can be adapted to diverse SIM illumination strategies by altering the known illumination patterns in the loss function, leading to resolution enhancements aligning with theoretical estimations.

Semiconductor laser networks underpin numerous applications and fundamental inquiries in nonlinear dynamics, material processing, illumination, and information handling. Still, the task of getting the typically narrowband semiconductor lasers to cooperate inside the network relies on both a high level of spectral homogeneity and a suitable coupling design. We report an experimental procedure for coupling a 55-element array of vertical-cavity surface-emitting lasers (VCSELs) by using diffractive optics in an external cavity setup. selleckchem Twenty-two of the twenty-five lasers were successfully spectrally aligned, each one connected to an external drive laser simultaneously. Further emphasizing this point, the array's lasers show substantial interconnection effects. Accordingly, we display the largest reported network of optically coupled semiconductor lasers and the initial in-depth investigation of a diffractively coupled system of this sort. Given the consistent nature of the lasers, the powerful interaction among them, and the capacity for expanding the coupling procedure, our VCSEL network represents a promising avenue for investigating complex systems, finding direct application as a photonic neural network.

Employing pulse pumping, intracavity stimulated Raman scattering (SRS), and second harmonic generation (SHG), efficiently diode-pumped passively Q-switched Nd:YVO4 lasers emitting yellow and orange light are developed. A Np-cut KGW, integral to the SRS process, enables the selection of either a 579 nm yellow laser or a 589 nm orange laser. A compact resonator design, integrating a coupled cavity for intracavity SRS and SHG, is responsible for the high efficiency achieved. The precise focusing of the beam waist on the saturable absorber ensures excellent passive Q-switching. At 589 nanometers, the orange laser's output pulses exhibit an energy of 0.008 millijoules and a peak power of 50 kilowatts. Conversely, the yellow laser's output pulse energy and peak power can reach 0.010 millijoules and 80 kilowatts at a wavelength of 579 nanometers.

Due to its substantial capacity and negligible latency, laser communication utilizing low Earth orbit satellites has become an integral part of modern communications. The amount of time a satellite remains operational hinges significantly on the battery's ability to withstand repeated charging and discharging cycles. Low Earth orbit satellites, frequently recharged by sunlight, discharge in the shadow, a process accelerating their aging.