Extensive numerical simulations have been carried out to verify the feasibility, security, and robustness of these four color image encryption schemes.A method is proposed and demonstrated to improve a diffraction grating displacement sensor to simultaneously achieve nanometer-level resolution and an extended range of operation. The method exploits the polarization phase-shifting optical path to extract two sinusoidal signals with a quadrature phase shift. The interpolation circuit is applied to nonlinearly convert two sinusoidal signals into a standard incremental AB quadrature digital signal, implementing an extended operation range with the magnitude of a laser coherence length. This work enables displacement measurement operated at large-scale range, and provides a significant guide for the design of a high performance micro-displacement sensor.Airborne particulate matter has become an emerging issue globally due to environmental degradation and the health risk it causes. Volatilization of weakly adsorbed particles onto quartz filter paper (QFP) limits its performance. The adsorption of particulate matter (PM10) onto QFP coated with different concentrations of graphene oxide (GO) was investigated to enhance the adsorption potential. https://www.selleckchem.com/products/Rapamycin.html Hummer's method was adopted to synthesize GO. QFPs were coated with different concentrations of GO using a spin coating technique to optimize the result. The morphology and microstructure of GO-QFP were characterized by various experimental techniques, like XRD, FTIR, EDX, and SEM. GO showed considerable affinity to aerosol particles for GO-QFP weighing 5 mg/ml, whereas adsorption of the coated samples before and after was significantly reduced. The high affinity to aerosol particles was due to dominated π-π interactions and the grooved regions formed on the GO layer. It was considered that the high surface to volume ratio of GO-QFP improves the adsorptive property of the QF and consequently enhances the performance of the filter paper.A void-free bonding technique was demonstrated for a large slab Nd YAG crystal with a bonding surface dimension of ∼160mm×70mm. By using the novel fluxless oxide layer removal technology, the indium-oxide barrier problem was resolved. With the help of electrochemical-polished indium solder and a plasma-cleaned heat sink, the solderability of the indium was enhanced; in particular, the contact angle of the solder was improved from 51° to 31°. With the largest-bonding-size slab, a single-slab laser created a maximum output power of 7.3 kW under an absorbed pump power of 12.8 kW, corresponding to an optical to optical efficiency of 57% and a slope conversion of 67.8%. By detecting the wavefront of the interferometer before and after bonding, the RMS of wavefront was 0.192λ and 0.434λ (λ=633nm), respectively. To the best of our knowledge, this is the largest void-free bonding size for a laser slab and the highest output power achieved from a single-slab crystal laser oscillator.A pump-probe setup including a Robert-cell-type delay stage is calculated and built in the presented study. The goal is to visualize laser beam material interactions upon highly repetitive ultrashort pulse irradiations by shadowgraph imaging, which makes a valuable contribution to clarify the occurring interaction phenomena in this field. Ultrashort laser pulses (λ=1030nm; τ H =400fs) are irradiated onto a bright-rolled stainless steel metal plate (AISI 316). The high-speed shadowgraph sequences are captured for the time-resolved imaging of plasma and shockwave evolution during material ablation. The captured time frame ranges from the time just before the next pulse irradiates the interaction zone until 2 µs after pulse irradiation. The first part of the experimental study features the shockwave dynamics and evolution of the laser plasma/ablation plume as induced upon single-pulse irradiations. It is shown that the expansion velocity of the shockwave decreases from 10 km/s shortly after pulse irradiation to 6.1 km/s at 41 ns after pulse irradiation. The second part deals with laser pulse trains by irradiating up to 10 pulses at 500 kHz pulse repetition frequency to the substrate. For increasing pulse numbers, the shadowgraphs show a steady increase in height and width of the laser plasma/ablation plume that were measured at 2.4 mm in height and 1.2 mm in width after the 10th pulse.This paper presents a soft-glass (SF-57) elliptical-spiral photonic crystal fiber with elliptical air holes for achieving high birefringence, large nonlinearity, and tailoring two zero-dispersion wavelengths (ZDWs) in the near-infrared region. A full-vector finite-element method with perfectly matched boundary layer is used to characterize the properties of the photonic crystal fiber for different ellipticity ratios. The designed fiber has a birefringence 4 times higher than the circular-spiral structure. There are two ZDWs at around 1.2 µm and 2.8 µm which can be finely tuned depending on the ellipticity ratios along with a large nonlinearity. Due to the superior guiding properties, the proposed structure can be used for polarization control and broadband supercontinuum generation.Underwater wireless optical communications is a promising technique for addressing short-range data networks, as it provides cost, performance, and complexity improvements as compared with other alternatives, such as acoustic communications or radio frequency links. It is a part of the optical wireless communications research area, since for these applications, broad optical sources such as visible LED lamps can be used. Unless those links are designed for short distances (about 1 m, as in data-muling services on internet-of-things submerged systems), they are still severely affected by channel perturbations, such as scattering due to the presence of particles. This effect is particularly important when considering sensing applications for algae or aquaculture farming, which are becoming a crucial economic resource in many maritime areas. In this work, the effects of moving microalgae on underwater short-range optical links are studied so as to estimate a model for this scattering under dynamic conditions. The statistical parameters over experimentally measured received signal level and signal-to-noise ratio (SNR) are calculated, and the experimental setup is described.