Phase retrieval is demonstrated without prior ex-situ phase stepping. Instead, correlation matrices are used to compensate for the displacement between reference acquisition and the probing of a PMMA target rod. The steps for improved measurements with more energetic laser systems are discussed. The final results are in good agreement with the theoretically predicted outcomes, demonstrating the applicability of this diagnostic to a range of laser facilities for use across several disciplines.A key technique in direct imaging of extrasolar planets with ground-based telescopes is extreme adaptive optics. It requires a wavefront sensor capable of achieving high accuracy with a small number of photons. Imada et al. [Appl. Opt.54, 7870 (2015)APOPAI0003-693510.1364/AO.54.007870] proposed a type of wavefront sensor that employs a point-diffraction interferometer (PDI). This type of sensor has problems concerning a low photon-usage efficiency and manufacturing feasibility. In addition, they did not give sufficient study on the optimum pinhole size. Here, we propose a novel PDI, with which these problems are overcome, and study the optimum pinhole size for it. The sensor is incorporated with birefringent crystal as the key component to achieve high efficiency and is feasible to manufacture realistically. We run numerical simulations to optimize the pinhole size, where the photon noise is evaluated.We investigate experimentally the phase retrieval of a Kolmogorov phase screen from very sparse data by modulating its amplitude with four binary masks and compare the retrieved phase screen to the ground truth measured with a surface profiler. Previously, we have shown in simulations that this kind of modulation can be successfully used for the phase retrieval of a Kolmogorov phase screen. After subtracting the ground truth from the retrieved phase screen, the root-mean-square error decreased from 0.14 µm to 0.10 µm. We conclude that a Kolmogorov phase screen can be recovered using simple modulation and very sparse data.The Goos-Hänchen (GH) shift caused by blue phosphorene/transition metal dichalcogenides (BlueP/TMDCs) and graphene surface plasma resonance (SPR) in Kretschmann configuration are studied theoretically. In this structure, graphene and BlueP/TMDCs coated on Cu thin film are optimized to improve the GH shift.  https://www.selleckchem.com/products/AP24534.html  The highest GH shift of sensor Cu-BlueP/WS2-graphene is 1004λ with three layers BlueP/WS2 and a graphene monolayer. For the sensing application, the sensitivity corresponding to the optimal GH shift is 3.199×106λ/RIU, which is 210.8 times higher than the traditional Cu film, 181.4 times higher than the Cu-BlueP/WS2 (monolayer) structure, and 56.6 times higher than the Cu-graphene structure. Therefore, the SPR sensor with high GH shift can be extensively used in the fields of chemical, biomedical, and environmental monitoring.We propose and experimentally demonstrate a passive and compact interleaver on a silicon on insulator (SOI) platform using a ring-assisted asymmetrical Mach-Zehnder interferometer configuration. The wavelength-insensitive couplers, i.e., multimode interference couplers and adiabatic 3-dB couplers, are introduced to eliminate the effect of an unequal splitting ratio and wavelength on crosstalk and the operating spectral range. In addition, there exists an inherent phase shift between the two couplers; the device can be fully passive and works well without additional thermal tuning. In the calculation, the influence of wavelength sensitivity of self-coupling coefficients and couplers on the performance of the interleaver is considered. The experiment shows that, by employing wavelength-insensitive couplers, the operating spectral range of the proposed interleavers was extended to be >140nm for all sorts of channel spacing and channel count. The measured free spectral range is 4.6 nm, and the crosstalk is as low as -46.6dB for the best case.In this paper, an analytical expression with a triple sum of the Hermite-Gaussian vortex beam (HGVB) propagating in a medium with a parabolic transverse spatial distribution of the refractive index is carried out. The intensity, phase, Poynting vector, and angular momentum of the HGVB are demonstrated analytically. The parabolic parameter, orders of the HGVB, and vortex topological charge affect the propagation properties, respectively. Also, the Poynting vector and angular momentum of the HGVB are shown so that we can further discover the properties. Furthermore, radiation forces are used to demonstrate the optical trapping ability of the HGVB, and several trapping positions are formed by the beam during propagation.At present, aluminum-based optical payloads are widely used in the aviation and aerospace field, and the demand for aluminum mirrors has become increasingly urgent in the visible light region. The main processing of an aluminum alloy mirror involves single-point diamond turning followed by a combined polishing process. Among these processes, magnetorheological finishing (MRF) is an important method for improving a surface figure. During the MRF process, excessive impurity contaminants are introduced into the surface of the aluminum mirror, thereby reducing surface reflectivity. In this paper, theoretical analysis and time-of-flight secondary ion mass spectrometry depth profiling were used to obtain the cause of pollution, and the process scheme of femtosecond laser cleaning was proposed. After verifying the feasibility, a new, to the best of our knowledge, process route was implemented on a Φ50mm aluminum mirror. Finally, the surface figure of RMS 0.022λ and the surface roughness of Ra 3.24 nm were obtained. In addition, reflectance in the visible light and near-infrared bands has increased by about 50%.Polarized light scattering measurements have the potential to provide improved characterization of natural particle assemblages in terms of particle size and composition. However, few studies have investigated this possibility for natural assemblages of marine particles. In this study, seawater samples representing contrasting assemblages of particles from coastal environments have been comprehensively characterized with measurements of angle-resolved polarized light scattering, particle size distribution, and particle composition. We observed robust trends linking samples containing higher proportions of large-sized particles with lower values of the maximum degree of linear polarization and the second element of the scattering matrix at a scattering angle of 100°, p22(100∘). In contrast, lower values of p22(20∘) were found in more non-phytoplankton-or inorganic--dominated samples. We also determined that three measurements involving the combinations of linearly polarized incident and scattered beams at two scattering angles (110° and 18°) have the potential to serve as useful proxies for estimating particle size and composition parameters.