Templedickson0819

In this paper, an optical guiding and docking scheme is designed, and a node integrating laser positioning guidance and communication functions is developed. Through experiments, it is verified that the laser docking system has the function of guiding and communicating the autonomous underwater vehicle (AUV) with the support of the seabed observation network. It can provide two-dimensional position information for underwater platforms to navigate the media to sea network nodes and enable visual contact between them. The integrated terminals are small enough (6 cm in diameter) to be installed on small underwater platforms, such as AUVs. To safely work at a depth of thousands of meters, the devices have cylindrical shapes rather than spherical shapes. However, the cylindrical shell confines the view angle of the receiver. An optical system and a photodiode array are adopted to enlarge the cylindrical-shaped receiver's view angle. The positioning algorithm is designed based on the optical lens system and the photodiode array. In a small-pool experiment, this system is tested to achieve a data rate of 1 Mbit/s at a distance of 4 m. Positioning algorithms are also confirmed preliminarily in the small-pool experiment, and the error of the positioning algorithm is discussed.The characteristics of laterally scattered light from nanoparticles can be experimentally studied by polarization imaging technology. This paper compares and analyzes the differences in polarization between nanoparticles and microparticles. Then, the influence of the incident light intensity on scattered light and the degree of polarization is studied. It is found that, when the concentration of nanoparticles is constant, the degree of polarization of scattered light is not affected compared with the scattered light intensity. Finally, the variation law of nanoparticle concentration and polarization is studied. It is found that, with the increase of particle concentration, the polarization of lateral scattered light increases and then decreases.As the main structure that induces aero-optical effects, the supersonic mixing layer is an essential structure in hypersonic flight vehicles with optical windows. The aero-optical effects of a Mc=0.17 supersonic mixing layer controlled by the ramp vortex generator array (RVGA) were investigated in detail using the nano-tracer-based planar laser scattering technique and ray tracing method. The incident locations and angles of the beam, and the mounting position of the RVGA, act as variables. In different cases, the optical path difference (OPD), Strehl ratio (SR), imaging displacement (ID), and bore sight error (BSE) are taken as evaluation parameters. Surprisingly, the length of the laminar section of the supersonic mixing layer varies little when the RVGA is applied. To reduce the aero-optical effects under our experimental conditions, the best incident angle is between 90º and 100º, and the position of the aperture should be carefully chosen to avoid the region of transition. A 10.75%-25.22% reduction of the average OPDrms and a 15.30%-33.99% reduction of the standard deviation of the OPDrms are achieved when the RVGA is applied, as well as an overall improvement of the SR, ID, and BSE. In our experimental circumstances, the supersonic mixing layer's aero-optical effects are suppressed to the full extent if the RVGA is mounted right at the trailing edge of the splitter.In this paper, we design a free-form off-axis three-mirror optical system with a low f-number and compact structure, which can be used as an infrared reflection imager. TPEN The initial structure is calculated from the near-axis optical transfer matrix based on third-order aberration theory. Particular constraints are designed to install all mirrors on the same substrate for simultaneous milling, which reduces the processing difficulty and effectively avoids errors caused by component assembly. Zernike free-form surfaces are introduced to correct aberrations. This optical system has a field of view of 5∘×5∘ and an f-number of 1.82; the modulation transfer function of the system is higher than 0.6 at 30 lp/mm. The results of the tolerance assignment of the system were verified by the Monte Carlo method, and the machining tolerance is reasonable and easy to achieve. This design not only improves the optical performance of the system but also enhances the feasibility of manufacturing.In this paper, we demonstrate a simple and cost-effective fiber chirped pulse amplification (CPA) laser system, where a nonlinear amplifier is employed to generate broadband seeding pulses. The nonlinear amplifier can generate stable pulses with 50 nm spectral bandwidth and linear chirp. With such a seeding configuration being adapted into a fiber CPA laser system, the output bandwidth can be expanded from 7 nm to 20 nm, with only minor changes to a standard industrial fiber CPA system. The increased bandwidth allows for pulse durations of less than 100 fs, which is significantly shorter than the original configuration's 250 fs. When combined with a Fourier pulse shaper, such a fiber laser system is expected to produce pulses with energy exceeding 100 µJ and duration shorter than 100 fs.Experiments based on a free-space platform have demonstrated that the weak-value amplification (WVA) technique can provide high sensitivity and precision for optical sensing and metrology. To promote this technique for real-world applications, it is more suitable to implement WVA based on an optical-fiber platform due to the lower cost, smaller scale, and higher stability. In contrast to the free-space platform, the birefringence in optical fiber is strong enough to cause polarization cross talk, and the amplitude-type noise must be taken into account. By theoretical analysis and experimental demonstration, we show that the optic-fiber-based WVA is robust in the presence of amplitude-type noise. In our experiment, even the angular misalignment on optical axes at the interface reaches 0.08 rad, and the sensitivity loss can be maintained at less than 3 dB. Moreover, the main results are valid to a simplified detection scheme that was recently proposed that is more compatible with the future design of optical-fiber-based WVA. Our results indicate the feasibility of implementing WVA based on optical fiber, which provides a possible way for designing optical sensors with higher sensitivity and stability in the future.We propose a design approach for a thin image scanner using the concept of an apposition compound eye comprising many imaging units that take only one pixel image. Although light shielding between adjacent imaging units is always one of the main issues for an artificial compound eye, a simple plane structure using three aperture array layers on two glued glass plates prevents such stray light. Our prototyped scanner, with only 6.8-mm thickness as a packaged module, has 632 microlenses with 200-dpi resolution, resulting in a field of view of 80 mm. The evaluated images show no ghost images.We propose a method for estimating the angle-of-arrival of an optical beam, which is based on angle-dependent properties of interference optical filters. One-filter and two-filter configurations for beam angle detection in one plane were investigated experimentally. By using off-the-shelf interference filters and a laser beam with a 4 nm broad spectrum at a 1030 nm center wavelength, an angle detection range of 1.6°-2.3° was achieved with an angle detection uncertainty standard deviation of less then 0.2% of the total beam angle detection range. The performance of the proposed beam angle detection method was compared with that of the segmented detector method under conditions of air turbulence. It was found that the proposed method is more resistant to turbulence-caused beam distortions and allows determination of the beam angle with higher precision.Using a short-wave infrared (SWIR) camera to improve daytime star detection ability has become a trend for near-ground star trackers. However, the noise of SWIR star images greatly decreases the accuracy of the attitude measurement results. Aiming at a real-time application of the star tracker, an adaptive section non-uniformity correction method based on the two-point correction algorithm for SWIR star images is proposed. The correction parameters of different sections are first calculated after the defective pixels are detected and excluded, and the real-time image is corrected using adaptive section parameters according to its gray value distribution. Finally, the defective pixels are compensated for by their adjacent corrected pixels. The correction results of both simulated and live-shot star images have verified the validity of the proposed method. It adapts to different sky background radiation, which is effective for the application of a star tracker. By comparing with other linear correction methods, it has the advantages of low calculation complexity, better real-time performance, and easier implementation in the hardware.In complex field of view (FOV) environments, a single camera's FOV measurement range is limited and cannot cover the entire object under test for global calibration. Multiple cameras are used mostly for large FOV environment measurements, but the traditional one- and two-dimensional targets used for global calibration in large FOV environments are prone to overlapping FOV. Furthermore, other large-sized targets are difficult to produce and process, and the laser projection method and plane mirror calibration methods are easily affected by the outdoor environment. To solve this problem, a non-common FOV binocular calibration method based on rigidly connected stereo targets is proposed. The calibration process is as follows First, the rigidly connected target, which is composed of two plane targets with a checkerboard, is placed in front of the two cameras, and the vision sensor captures the corresponding sub-target image; then, the target is moved multiple times, and the transformation relationship between multiple vision sensors is obtained according to the spatial constraint characteristics of the rigidly connected target. Hence, the method overcomes the limitation of the non-overlapping FOV calibration method that relies on large measuring instruments. The experimental results show that the RMS error of the 13 mm distance is 0.16 mm. The proposed method is effective, simpler to operate than other methods, and does not rely on the constraint of complex targets. More importantly, this measurement method solves the difficult problem of measurement in non-public FOV, meeting the requirements of large FOV measurement ranges.The accuracy of reconstructing depth maps or performing digital refocusing in light field cameras depends largely on how well the spatial and angular samples of light rays can be obtained. Ray sample errors induced by optical aberrations in a light field camera may be digitally corrected using the ray tracing data when its nominal lens design is available. However, the most commonly nominal lens prescription is not accessible to end users. Additionally, even if available, due to tolerances in optomechanical design, the ray tracing data can be inaccurate. We propose a calibration method based on measurements of fiducial markers on a checkerboard for modeling the imaging properties of light field cameras. The calibration accounts for vignetting, transverse ray errors, as well as pupil aberration, and can be applied to light field camera modeling of arbitrary pupil sampling systems. We further demonstrate the utility of the method for calibrating a tri-aperture camera that captures simultaneous stereo views via artificially induced transverse ray errors.