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Compared with traditional photonic crystal fiber, the designed DLFF makes the sensor configuration simple to fabricate as well as a potential candidate for developing biochemical sensors and portable devices.We investigate a systematic improvement for 3D range-gated imaging in scattering environments. Drawbacks including absorption, ambient light, and scattering effect are studied. The former two are compensated through parameter estimation and preprocessing. With regard to the scattering effect, we propose a new 3D reconfiguration algorithm using a Bayesian approach that incorporates spatial constraints through a general Gaussian Markov random field. The model takes both scene depth and albedo into account, which provides a more informative and accurate restoration result. Hyper-parameters for the statistical mechanism are evaluated adaptively in the procedure and an iterated conditional mode optimization algorithm is employed to find an optimum solution. The performance of our method was assessed via conducting various experiments and the results also indicate that the proposed method is helpful for restoring the 2D image of a scene with improved visibility.We propose a phase retrieval method using axial diffraction patterns under planar and spherical wave illuminations. The proposed method uses a ptychographic iterative engine (PIE) for the phase retrieval algorithm. The proposed approach uses multiple diffraction patterns. Thus, adjusting the alignment of each diffraction pattern is mandatory, and we propose a method to adjust the alignment. In addition, a random selection of the measured diffraction patterns is used to further accelerate the convergence of the PIE-based optimization. To confirm the effectiveness of the proposed method, we compare the conventional and proposed methods using a simulation and optical experiments.We present a hybrid microintegrated diode laser module developed for iodine spectroscopy on board a sounding rocket. The laser module is based on a master-oscillator-power-amplifier concept an extended cavity diode laser serves as the master oscillator, and a ridge-waveguide semiconductor optical amplifier provides the power boost. The module's form factor and mass correspond to 12.5×7.5×2.3cm3 and 750 g, respectively. With an electrical power of 3.75 W supplied to the module, 570 mW of optical power is provided out of a polarization maintaining optical fiber at 1064.490 nm with a technical linewidth of 13 kHz (55 kHz) at a 1 ms (10 ms) time scale. The laser module has successfully passed vibration tests at a level of 8.8g R M S . A nominally identical module has recently been used to demonstrate, for the first time, precision iodine spectroscopy in space.Non-diffracting optical beams and their structured versions have been extensively studied, theoretically and experimentally, over the last two decades, rendering important applications in fields such as imaging, microscopy, remote sensing, optical manipulation, free space optics, etc. In this paper, we theoretically construct arrays of non-coaxial structured non-diffracting beams by using the so-called frozen wave method. We also develop techniques based on polarization allocations and apodizations to mitigate undesirable interferences among neighboring beams. https://www.selleckchem.com/products/lys05.html Our results can find interesting applications in all fields that benefit from the use of non-diffracting beams.Digital holographic microscopy is becoming increasingly useful for the analysis of marine plankton. In this study, we investigate autofocusing and image fusion in digital holographic microscopy. We propose an area metric autofocusing method and an improved wavelet-based image fusion method. In the area metric autofocusing method, a hologram image is initially segmented into several plankton regions for focus plane detection, and an area metric is then applied to these regions. In the improved wavelet-based image fusion method, a marked map is introduced for labeling each plankton region with the order of refocus plane images that accounts for the most pixels. The results indicate that the area metric autofocusing method applied to each plankton region provides a higher depth resolution accuracy than a number of general autofocusing methods, and the mean accuracy increases by approximately 33%. The improved wavelet-based image fusion method can fuse more than nine reconstructed plane images at a time and effectively eliminate fringes and speckle noise, and the fused image is much clearer than that of a general wavelet-based method, a sparse decomposition method, and a pulse-coupled neural networks method. This work has practical value for plankton imaging using digital holographic microscopy.Anamorphic lenses, with different optical powers along the tangential plane and the sagittal plane, are calibrated in this paper. The imaging model for anamorphic lenses is introduced. Compared with the pinhole model, it has two more intrinsic parameters the anamorphic distance and the anamorphic angle. The anamorphic lens has two optical centers one is in the tangential plane and the other is in the sagittal plane. The distance between the two optical centers is the anamorphic distance. The anamorphic angle refers to the angle between the camera coordinates and the pixel coordinates in the CCD plane. Formulas determining the initial value of the anamorphic distance are provided. Two experiments are conducted for the anamorphic lens calibration. As a comparison, the anamorphic lens is calibrated using the anamorphic imaging model and the pinhole model, respectively. The calibration accuracy can be improved remarkably if the anamorphic imaging model is applied, and calibrated results for the anamorphic distance and the anamorphic angle are very stable for different positions of the calibration target, which shows the validity and effectiveness of the anamorphic imaging model for anamorphic lens calibration.Because the physical properties of lithium niobate (LiNbO3) strongly depend on composition, accurate and convenient methods for the determination of the composition are of great significance. Although several optical methods, including the measurement of UV absorption edge, the birefringence, and the second-harmonic generation, have been proved to be convenient for an accurate and fast standard determination of composition in LiNbO3 single crystals, their research and commercial applications are limited by the doping component and the complex nonlinear relationships. Based on preliminary work, a novel optical method to determine the composition of LiNbO3 crystals by digital holography is proposed. This method is based on the static internal field, which is obtained by means of the three-dimensional (3D) static measurement of the phase difference between antiparallel poling states without applying external voltage by digital holography. In order to investigate the influences of composition and doping on the static internal field in LiNbO3 crystals, the measured static internal fields from various LiNbO3 samples with different stoichiometry, doping type, and doping level are summarized and compared.

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