Since the optical tweezers technology was discovered in 1986, the study and application of the mechanical effect of light has become an important branch of optical research. Unlike conventional microscope-configured optical tweezers platforms, optical tweezers based on ring-core fibers offer the convenience of more dimensional particle manipulation and separate the microscopic system from the manipulation system. The optical tweezers can capture particles, but if you want to further manipulate the particle's attitude, you need an optical micro-optic hand based on a multi-core fiber. If you want to emit the captured particles, you need an optical gun based on a coaxial dual-waveguide fiber. This article mainly introduces the design of optical tweezers, optical hands and optical guns based on different kinds of optical fibers and their manipulation effects on particles.

Micro-/nanomotors(MNMs)can perform autonomous motions, and have potential revolutionary applications in fields such as biomedicines, micro-nanofabrication and environmental detection and remediation. After briefly introducing the basic concept, propulsion mechanisms, construction strategy and research status of micro-nanomotors, this paper will focus on biocompatible Mg-based micromotors, which have firstly been developed in our research group, and free swimming functionalized sperm micromotors with intrinsic chemotactic motile behavior in biological and environmental media. Then, the light-controlled MNMs of various structures including Janus, single-layered tubular and isotropic structures are demonstrated. These intriguing properties offer them ample opportunities to act as motile platform to manipulate and assemble micro-/nanocargoes in highly sophisticated ways. In the end, the prospects about MNMs operating in living bodies, which should have powerful thrusts, specific sensing, external tracking and self-targeting in physiological environment like blood vessels are also presented.

A thin film thermocouple sensor directly deposited on Ni-based superallo is studied in this paper. According to the high temperature and harsh environment of aero-engine, the layer structure of the sensor is designed. Using the magnetron sputtering technology to deposite the membrane transition layer of NiCrAlY, the thin film insulating layer and protective layer are fabricated by the method of E-beam evaporation and RF-magnetron sputtering techniques. The Pt10Rh/ Pt sensitive layers of thin-film are prepared by DC magnetron sputtering technology. Test results show that the maximum operating temperature is 1 100 ℃. The seebeck coefficient is 8.26 μV/℃. The maximum temperature error is 0.93%. The service life is over 20 h. The results show that the thin-film thermocouple can withstand the harsh test environment of aero-engine, and the accuracy of the measurement’s local temperature is improved. The important basis for the life expectancy of the turbine cascade and the design of cooling structure is provided.

In order to quantitatively detect the physical properties and structural parameters of subsurface defects in materials by photothermal radiation technology, the finite element analysis method is used to simulate the steady state fluctuation temperature field of the material containing defects. An empirical formula for determining the depth and boundary of blind holes is proposed by analyzing the photothermal radiation signals. The relationship between photothermal radiation signals and defect shapes and thermal properties is revealed. The diameter and depth of the flat bottom blind holes with diameters of 1.5 mm, 2.0 mm, 2.5 mm, and depths of 0.2 mm and 0.4 mm, respectively, are measured by photothermal radiation techniques. The experimental results show that the diameter detection error is less than 15%, and the depth detection error is less than 10%. The effectiveness of the method for quantitative detection of defects by means of finite element analysis is verified by photothermal radiation detection experiment.

The geometric topological structures with different structural parameters are designed, and the electromagnetic shielding effectiveness of each geometric topological structure is compared and analyzed. The infrared transmittance formulas of each geometric topology are established and verified by computer image processing and experiment. The high frequency structure simulation software(HFSS)is used to simulate each geometric topology, and the electromagnetic shielding effectiveness of different geometric topologies in 12～18 GHz band is obtained. By comparing the electromagnetic shielding effectiveness of different geometric topological structures, the geometric topology with the highest electromagnetic shielding effectiveness under the same conditions is determined. The object of cross topology is obtained by lithography, and its electromagnetic shielding effectiveness is tested by network analyzer. The test results of cross topology show that the difference between measured and simulated electromagnetic shielding effectiveness tends to increase when the frequency increases.

The detection range of the infrared system is one of the key indexes of the photoelectric system, which determines the overall performance of the system.It is practical significance to evaluate the detection range of infrared system under laboratory conditions, which is not limited by weather or site.In this paper, starting from the relationship between the output signal of the detector and the target temperature of the blackbody, the expression of NETD is derived, the little Hudson formula is expressed by NETD, and the correctness of the formula is verified. The error between the index derived by this method and the theoretical calculation index is within 10%, which is feasible in practice.

With the development of optical fiber technology, it has been widely used in astronomical observation instruments. In astronomical observation instruments, the number of optical fibers usually reaches several thousand. When the spacing of optical fibers is too small, the output spectra is liable to overlap. Without changing the structure, the aliasing spectra is separated by software method, assuming that the intensity distribution of the output spectra is in the form of Gauss function, and the aliasing spectra is separated by Gauss function fitting method. Compared with the output spectrum when the distance between fibers is wider, a better separation effect is obtained. The minimum mean square deviation is 1.43. The results show that this method is feasible in the separation of aliasing spectra.

Different targets in space have different physical and geometry characteristics. RCS(Radar Cross-Section)is one of the most important characteristics of targets, so it is a very important method to classify targets based on RCS data. LPC(Linear Predictive Coding)is used to process RCS data in order to obtain LPC coefficients of them. Then the LPC coefficients are used as feature vectors for targets classification and recognition. In this way, the classification rate can be up to 80%~90% when classifying two targets. And the classification rate can be up to 50%~80% when classifying three targets. This method can effectively improve the radar automatic classification capability so as to track targets semi-automatically and automatically.

The active sonar target echo is seriously interfered by the marine environment noise. The long-range detection echo signal is weak, and the target azimuth estimation accuracy is low. Moreover, the traditional matrix spatial spectrum estimation method needs to satisfy the Nyquist sampling rate and the data acquisition amount is large. Based on the spatial sparseness of the signal and the echo signal bright spot model, the spatial azimuth estimation technique based on compressed sensing is studied. In the case of limited physical aperture of the receiving matrix, the linearaperture(LP) virtual array method is used to improve the aperture size of the array, and the compressed echo(CS)algorithm is used to reconstruct and recover the target echo signal. The data is simulated and analyzed. The resolution of the spatial spectrum estimation of the array is improved, and the noise interference is effectively suppressed.

Chaff cloud is widely used in the field of electromagnetic interference. Chaff clouds are cheap to made and have a good interference performance. However, there are many difficulties in electromagnetic scattering evaluation of chaff cloud. One of the core problems is to establish a proper diffusion model of the chaff cloud. In fact, there are many unsolved problems in chaff cloud diffusion simulation with aerodynamic method. Therefore, the diffusion process of chaff cloud can be studied by means of high-speed photography. How to obtain the length of chaff elements from the picture is a problem that must be solved. In this paper, support vector machine and HOG algorithm are used to extract the length of single chaff element from the image. The simulation results show that the accuracy of the proposed chaff length recognition algorithm can reach 99%, and the recognition time of a single image is less than 1 s. It improves processing efficiency of chaff cloud diffusion modeling.

Aiming at the key point detection problem of UAV, a key point detection algorithm based on cascade neural network is proposed. The neural network used in the algorithm is cascaded into two parts: network1 detects the whole target; network2 receives the target image as input, then outputs the location information of the key points on the target. Aiming at the low real-time problem caused by the existing methods by deepening the accuracy of the network, this algorithm introduces two kinds of cross-level connection methods to enhance the reuse of global information and improve the accuracy of key point positioning. At the same time, it reduces the amount of network parameters and improves the real-time performance by using depth separable convolutions. The test data shows that the relative error of key point positioning is 0.03 in complex background, and the average running speed is 28 f/s on Nvidia Geforce GTX 1080ti. While guaranteeing high positioning accuracy, it meets the real-time requirements of current applications.

By analyzing urgent demands of electro-optical cooperative detection in modern naval battle, the necessity of improving effectiveness of systematic detection in ship formation. By overview the domestic and foreign research status, the gaps are pointed out in comparison. As a case of synthetical EO/IR surveillance and response equipment, the key techniques in electro-optical cooperative detection, such as cooperative tracking, recognition and passive ranging, are selective analysis subsequently. The corresponding approaches of solution are proposed: deep learning based divided OE recognition technique by layer time series, tracking theory base on pattern similarity measurement analysis and grey prediction, infrared synthetical passive ranging theory based on multiple frame filtering.

The Nd∶YVO4 crystal generally applies 808 nm laser as the pumping source, but its strong absorption leads to serious thermal effect, which limits the laser output power and beam quality. In this paper, the 888 nm laser with relatively weak absorption is used as the in-band pumped source, which significantly reduces the thermal effect of Nd∶YVO4 crystal under high pump power. Combined with our self-developed all-fiber picosecond seed laser, the 1 064 nm picosecond laser output with pulse width of 12.1 ps, repetition frequency of 100~500 kHz, max single-pulse energy of 250 μJ is realized. The regenerative amplifier has the advantages of small size, stable pulse, high single-pulse energy, high conversion efficiency and good beam quality. It can be used as the laser source of ultrafast laser processing system or after further amplification.

The atomic cooling and trapping process of the cold atom interferometer has high requirements on the linewidth of the laser. In order to obtain a 780 nm laser beam that meets the experimental requirements, the fine spectral lines 5S1/2F = 1 5P3/2F = 3 of the Rb87 ’s D2 line are used as frequency reference, and the modulation transfer frequency stabilization(MTS)method obtains a modulation transfer spectrum without the Doppler background. In the experiment, using this spectral signal as the error signal can stabilize the laser frequency at the rubidium atom reference frequency for up to 20 hours, and the linewidth is enough to meet the requirements of laser cooling atom experiments.

The operation of small field of view star tracker assisted by inertial platform is affected by many complex factors, such as meteorological conditions, inertial navigation accuracy, servo angle measurement accuracy and so on. In order to analyze the error factors quantitatively and improve the accuracy of celestial navigation, the star map simulation technology of star tracker is studied. According to the principle of star tracker, the mathematical model of star map simulation is derived and established. According to the model, the simulation software of star map is designed, and the influence of various error factors on the measurement effect is simulated. The simulation results verify the correctness of the model, which can provide theoretical simulation for the design of star tracking and celestial navigation algorithm.

It is the most accurate method to obtain the attitude information of the spacecraft by using the stellar as the observation datum, and the key of this method is to identify the stellar. The stellar identification is to find a guide stellar corresponding to the observed stellar in the guide stellar catalog. In this paper, the construction of the guide stellar feature database and the stellar identification methods are studied, and a new celestial sphere stellar identification method is proposed by using data compression. Firstly, many suitable stellars are screened to construct the standard guide catalogue according to the ability of the stellar detection limit. And the lossless compression of guide stellar feature database is constructed according to the standard guide catalogue and detector field angle. Secondly, the observation triangle of angular distance of identification stellars is constructed by using the position information of detector and the number of stellars. And the stellar number and angular distance are extracted and constructed state matrix from the compression guide stellar feature database; Thirdly, by comparing the angular distance of observation triangle with the angular distance of guide stellar feature database, the identification of state matrix is marked. And the angular distance of guide stellar feature database corresponding to the identification of state matrix is extracted and is compared with the angular distance of observation triangle to identify the stellar. The field of detector is 10°×10°, the detection limit is 6.5 magnitude star, and there are 9 040 guide stellar in the guide stellar catalog. The results show that this method can be reduce search time and space complexity by using the state matrix.

At present, particle filter is widely used in underwater physical field auxiliary navigation. Aiming at the defect of particle degradation caused by long-term particle filtering, an improved particle filtering method is proposed in this paper. The innovation of this method is that the navigation positioning error and terrain measurement error are estimated in real time in the filtering, and each particle resampling strategy is adjusted according to the estimation result. The newborn particles are randomly distributed in the pool of error while reflecting the probability density of the carrier being located in the pool of error. Using the algorithm for underwater terrain-assisted inertial navigation simulation, compared with the traditional filtering method, the positional error can be quickly reduced, meanwhile the method can avoid the filter divergence caused by particle degradation, and the final filtering accuracy is improved. By this method, the positioning error accumulated by long-term inertial navigation is reduced from 900 m to 50 m within 500 s. This method will have broad application prospects in the field of underwater multi-physics assisted navigation.