Accordingly, a straightforward fabrication method for Cu electrodes, achieved via selective laser reduction of CuO nanoparticles, was presented in this paper. Laser processing parameters, such as power, scanning speed, and focus, were fine-tuned to create a copper circuit with a resistivity of 553 micro-ohms per centimeter. Drawing upon the photothermoelectric characteristics of the copper electrodes, a white-light photodetector was then produced. The detectivity of the photodetector, at a power density of 1001 milliwatts per square centimeter, reaches 214 milliamperes per watt. check details This method, specifically designed for fabricating metal electrodes or conductive lines on fabric surfaces, also provides detailed procedures for creating wearable photodetectors.
In the domain of computational manufacturing, a program for monitoring group delay dispersion (GDD) is introduced. We compare two computationally manufactured dispersive mirrors by GDD: one for broadband applications and another for time monitoring simulation. The results from dispersive mirror deposition simulations, employing GDD monitoring, presented specific advantages. An analysis of the self-compensation inherent in GDD monitoring is undertaken. The precision of layer termination techniques, through GDD monitoring, could potentially be applied to the production of further types of optical coatings.
An approach to quantify average temperature shifts in deployed optical fiber networks is presented, using Optical Time Domain Reflectometry (OTDR) and single-photon detection. This study develops a model describing how changes in the temperature of an optical fiber affect the time-of-flight of reflected photons, measured from -50°C to 400°C. Utilizing a setup encompassing a dark optical fiber network spanning the Stockholm metropolitan area, we verify the capacity to gauge temperature changes with an accuracy of 0.008°C over kilometer-long distances. Both quantum and classical optical fiber networks are enabled for in-situ characterization using this approach.
We present the mid-term stability development of a table-top coherent population trapping (CPT) microcell atomic clock, formerly susceptible to light-shift effects and discrepancies in the cell's inner atmosphere. Employing a pulsed symmetric auto-balanced Ramsey (SABR) interrogation technique, along with temperature, laser power, and microwave power stabilization, the light-shift contribution is now minimized. Moreover, the cell's internal gas pressure variations have been substantially reduced by employing a micro-fabricated cell incorporating low-permeability aluminosilicate glass (ASG) windows. Upon combining these approaches, the clock's Allan deviation is measured as 14 picaseconds per second at 105 seconds. The stability of this system over a 24-hour period is comparable to the best microwave microcell-based atomic clocks currently on the market.
In photon-counting fiber Bragg grating (FBG) sensing systems, a narrower probe pulse width, despite improving spatial resolution, inevitably leads to spectral broadening, as dictated by Fourier transform theory, thus impacting the system's sensitivity. Within this investigation, we analyze the impact of spectral widening on the performance of a photon-counting fiber Bragg grating sensing system employing dual-wavelength differential detection. In conjunction with the developed theoretical model, a proof-of-principle experimental demonstration was achieved. Our analysis demonstrates a numerical association between the sensitivity and spatial resolution of FBGs across different spectral widths. Our study on a commercially produced FBG, with a spectral width of 0.6 nanometers, showed an optimal spatial resolution of 3 millimeters and a sensitivity value of 203 nanometers per meter.
Integral to an inertial navigation system is the gyroscope's function. Gyroscope applications rely on both high sensitivity and miniaturization for success. A nitrogen-vacancy (NV) center, contained within a nanodiamond, is held aloft using either optical tweezers or an ion trap apparatus. The Sagnac effect underpins a scheme for ultra-high-sensitivity angular velocity measurement through nanodiamond matter-wave interferometry. Estimating the proposed gyroscope's sensitivity involves accounting for the decay in the nanodiamond's center of mass motion, alongside the dephasing of its NV centers. The visibility of Ramsey fringes is also calculated, which is pertinent to determining the gyroscope sensitivity's limiting factor. Within the confines of an ion trap, a sensitivity of 68610-7 rad/s/Hz is observed. With the gyroscope's incredibly small operating area (0.001 square meters), on-chip fabrication could become a realistic possibility in the near future.
Self-powered photodetectors (PDs) with low-power consumption are vital for next-generation optoelectronic applications, supporting the necessities of oceanographic exploration and detection. Self-powered photoelectrochemical (PEC) PD in seawater, based on (In,Ga)N/GaN core-shell heterojunction nanowires, is successfully demonstrated in this work. check details The PD's current response in seawater is markedly faster than in pure water, owing to the prominent overshooting of current in both directions, upward and downward. The enhanced speed of response allows for a more than 80% decrease in the rise time of PD, while the fall time is reduced to only 30% when operated within a saltwater environment instead of pure water. The instantaneous temperature gradient, carrier accumulation, and elimination at semiconductor/electrolyte interfaces during light on and off transitions are crucial to understanding the overshooting features' generation. A key finding from experimental analysis is that Na+ and Cl- ions are proposed as the primary factors influencing PD behavior in seawater, substantially enhancing conductivity and accelerating the oxidation-reduction process. The development of novel, self-powered PDs for underwater detection and communication is facilitated by this impactful work.
This paper proposes a novel vector beam, designated the grafted polarization vector beam (GPVB), a combination of radially polarized beams with different polarization orders. Compared to the tightly focused beams of conventional cylindrical vector beams, GPVBs showcase more adaptable focal field designs due to the adjustable polarization order of their two or more attached components. The GPVB's non-axisymmetric polarization, resulting in spin-orbit coupling within its high-concentration focal point, facilitates the separation of spin angular momentum and orbital angular momentum in the focal plane. The polarization order of two (or more) grafted sections is key to effectively modulating the SAM and the OAM. Additionally, adjustments to the polarization arrangement of the GPVB's tightly focused beam allow for a reversal of the on-axis energy flow from positive to negative. The outcomes of our research demonstrate greater flexibility and potential uses in optical trapping systems and particle confinement.
A novel simple dielectric metasurface hologram is proposed and engineered in this work, combining electromagnetic vector analysis with the immune algorithm. The resulting design effectively demonstrates holographic display of dual-wavelength orthogonal linear polarization light within the visible spectrum, thereby addressing the problem of low efficiency in traditional methods and enhancing the diffraction efficiency of the metasurface hologram. A titanium dioxide metasurface nanorod, featuring a rectangular shape, has been thoroughly optimized and designed for specific functionality. Incident x-linear polarized light at 532nm and y-linear polarized light at 633nm generate unique display images with low cross-talk on a common observation plane. The simulation demonstrates 682% and 746% transmission efficiencies for x-linear and y-linear polarization, respectively. check details The metasurface is then manufactured via the atomic layer deposition process. Experimental data corroborates the design's predictions, showcasing the metasurface hologram's full potential for wavelength and polarization multiplexing holographic display. This method holds significant promise for diverse applications, including holographic display, optical encryption, anti-counterfeiting, and data storage.
The sophisticated, substantial, and costly optical instruments employed in existing non-contact flame temperature measurement procedures limit the practicality of their use in portable devices and high-density distributed monitoring systems. A novel flame temperature imaging approach, based on a single perovskite photodetector, is presented in this work. To create a photodetector, high-quality perovskite film is epitaxially grown on a SiO2/Si substrate. The Si/MAPbBr3 heterojunction's impact results in an extended light detection wavelength, stretching from 400nm to 900nm. By implementing deep learning, a perovskite single photodetector spectrometer was created for the purpose of flame temperature measurement via spectroscopy. The temperature test experiment employed the spectral line of the K+ doping element as a means to determine the flame temperature. From a commercially sourced blackbody standard, the wavelength-dependent photoresponsivity function was derived. A regression-based solution to the photoresponsivity function, utilizing the photocurrents matrix, facilitated the reconstruction of the spectral line belonging to K+. A scanning process of the perovskite single-pixel photodetector was employed to ascertain the NUC pattern. The final image of the flame temperature, of the modified element K+, presented an accuracy of 95%. The technology facilitates development of flame temperature imaging devices that are highly accurate, easily transported, and cost-effective.
To improve the transmission of terahertz (THz) waves in the air, we propose a split-ring resonator (SRR) structure with a subwavelength slit and a circular cavity sized within the wavelength. This structure is engineered to enhance the coupling of resonant modes, thereby providing substantial omni-directional electromagnetic signal gain (40 dB) at a frequency of 0.4 THz.