Strandreece2261

A surface plasmon resonance (SPR) temperature sensor based on a photonic crystal fiber (PCF) filled with silver nanowires is proposed in this paper. We inject ethanol solution filled with silver nanowires into the grapefruit PCF to realize temperature sensing. The sensitivity of the sensor can reach -433pm/∘C by numerical simulation, and the experimental result is -160pm/∘C. Simulations and experiments show that the wavelength of the resonance peak will blueshift with the invalidity of silver nanowires, and the resonance effect of the sensor will weaken. It can provide reference for the realization and application of other SPR sensors based on PCF.Polarized light absorption in photoalignment material induces anisotropic long-range interactions that orient liquid crystals. The main physical mechanisms behind anisotropic interactions are photocrosslinking and photodestruction of polymers, and photoisomerization and photorotation of azo dyes. Investigation of AtA-2 azo dye azimuthal anchoring versus exposure dose revealed the presence of an unusually strong anchoring peak at low doses, which is beyond our understanding of the known mechanisms. Here we explain these observations and demonstrate the existence of a photoalignment mechanism based on photoinduced hole dipole moments in the azo dye layer. Strong azimuthal anchoring energy >2×10-4J/m2 is obtained with a less then 0.5J/cm2 exposure dose.We demonstrated the regenerative amplification of picosecond laser pulses generated by a gain-switched laser diode at 640 nm with a PrYLF crystal that was continuously pumped by a multimode blue laser diode. A 0.7-pJ seed pulse energy sufficiently suppressed the self-oscillation in the amplifier. The amplified pulse energy reached 33 µJ at a repetition rate of 10 kHz. The spatial beam quality was nearly TEM00. We also demonstrated second- and third-harmonic generation and obtained 320- and 213-nm pulse energies of 18 and 0.83 µJ at 10 kHz.A noncontact method to identify sparsely distributed plastic pellets is proposed by integrating holography and Raman spectroscopy in this study. Polystyrene and poly(methyl methacrylate) resin pellets with a size of 3 mm located in a 20 cm water channel were illuminated using a collimated continuous wave laser beam with a diameter of 4 mm and wavelength of 785 nm. The same laser beam was used to take a holographic image and Raman spectrum of a pellet to identify the shape, size, and composition of material. Using the compact system, the morphological and chemical analysis of pellets in a large volume of water was performed. The reported method demonstrates the potential for noncontact continuous in situ monitoring of microplastics in water without collection and separation.The kernel correlation filter (KCF) tracking algorithm encounters the issue of tracking accuracy degradation due to large changes in scale and rotation of aerial infrared targets. Therefore, this paper proposes a new scale estimation KCF-based aerial infrared target tracking method, which can extract scale feature information of images in the frequency domain based on the distribution characteristics and change laws of frequency-domain energy. In addition, the proposed method can improve the accuracy of target scale information estimation. First, the KCF tracking algorithm is used to obtain the target position. Then, spectral eigenvalues are calculated as eigenvectors, and frequency-domain rotation scale invariance is adopted to extract the eigenvector between two frames as the target rotation change information. Reverse rotation is performed on the current frame spectrum map for isolating the effects of target rotation on scale information estimation. 3-Deazaadenosine clinical trial Then, the current target scale is estimated on the basis of the eigenvectors between the adjacent frames. Finally, the length-to-width ratio and the scale of the tracking box are updated on the basis of the target rotation information, which improves the adaptability of the tracking box to changes in the target scale and rotation. The results indicate that the proposed algorithm is suitable for stable tracking of target scales and rapid changes in attitudes. The average tracking accuracy and the average success rate of the algorithm are 0.954 and 0.782, which represent improvements of 5.3% and 18.9%, respectively, compared with the KCF algorithm. The average tracking success rate is improved by 4.1% compared with the discriminative scale space tracker algorithm, and the average tracking performance is better than that of related filter tracking algorithms based on other scale estimation methods.A coherent laser range finder based on optical phase modulation and phase shift measurement is presented. In the proposed laser range finder, the emitted laser is modulated by an electro-optic phase modulator using a 20 MHz sine signal, and the received laser is mixed with a local oscillator using a 90° optical hybrid. Compared with traditional laser phase shift range finders, the proposed laser range finder can measure the velocity and range at high precision simultaneously. An algorithm to calculate the range and velocity is deduced. Our preliminary experiments on moving targets indicate that when the measurement rate is 100 kHz, the root mean square errors of range and velocity, respectively, are 9.35×10-4m and 4.74×10-4m/s.A tri-layer metamaterial structure with enhanced absorption is demonstrated at infrared wavelengths by coating the top surface of the metamaterial absorber with an additional thin layer of dielectric material. The metamaterial absorber, which consists of a micrometer-sized metallic circular patch separated from a metal ground plane by a dielectric spacer layer, when coated with a supplementary protective dielectric layer on the top, shows a spectral red shift of the peak absorption along with a change in the absorption amplitude. The increase or decrease in absorption arises basically from an interference phenomenon of light reflected from the surface of the protective dielectric and the surface of metamaterial structures, and is highly dependent on the thickness of the top dielectric layer. The protective dielectric coatings provide an alternative way to modify and optimize the absorption in a metamaterial absorber along with a robustness that protects metamaterial structures from environmental and mechanical degradation.