Using phase-screen approximation, the field distribution of laser beams propagating through atmospheric turbulence is calculated and simulated. The wavefront phase of the distorted beam in turbulence is also analyzed in terms of the high-frequency phase proportion and the number of branch points. Furthermore, considering the coupling between deformable mirror actuators, the model for estimating the physical limit of phase correction is built up by using the method of high-pass filtering including a smoothing factor of mirror actuator. The influence of turbulence intensity and propagation distance on the physical limit of phase correction is analyzed quantitatively. The results show that in a certain range, the proportion of high frequency in distorted phase increases obviously and the number of branch points grows gradually with the increase of turbulence intensity and propagation distance; the correction effect of laser beams in turbulence would be influenced mainly by the proportion of high-frequency in distorted phase and the number of branch points, and the greater the proportion of high frequency phase or the more the number of branch points is, the worse the correction effect of adaptive system would be.

The research of scattering property of small particles in electromagnetic beams has comprehensive applications in fields such as environmental monitoring. The electromagnetic beam is expanded in series, and the theoretical solutions of the internal fields for small particles as well as the physical significances of the items in these series are developed. Taking the elliptical beam as an example, the internal electric field and the changes of the ratio of the latter item to the former of the series, versus both the distance and the frequency are simulated. The scattering property of small particles in an elliptical Gaussian beam is investigated. By simulations, the effects of the beam waist and the frequency on scattering property are analyzed. The validity of the algorithm used is demonstrated. Results show that the beam waist may improve notably the particle′s identification, the scattering field of higher order item is much smaller than that of lower order item, and the power order of coordinates in the solution of internal field, speaking to a Rayleigh particle, is always equal to that of coordinates in the incident beam. The method used is simple and has explored a new way for scattering from particles in electromagnetic beams.

The effect of primary aberration and high-order aberration, especially spherical aberration, on imaging of flat-field holographic concave gratings is analyzed by using geometrical aberration theory. The difference between design results when spherical aberration is corrected or not is discussed through a specific design case, for situation of wide wave-range and narrow wave-range, respectively. Analysis is made through comparison of the spectral image size and the geometrical aberration coefficients. It is discovered that, for wide wave-range grating, the image size is determined mainly by primary aberration. Spherical aberration can be ignored during grating design procedure because the effect of spherical aberration is much less than that of primary aberration. But in the case of narrow wave-range grating, the effect of spherical aberration becomes significant because the defocus aberration is very small. The spherical aberration must be corrected in the design procedure when a much better imaging quality is expected.

A temperature sensor by using an alcohol-filled side-hole fiber (SHF) based Sagnac interferometer is proposed and experimentally demonstrated. SHF is a highly birefringent fiber, which has two air holes running aside the core in the cladding of the fiber. Temperature changes the refractive index of the alcohol liquid filled in the air holes of the SHF, leading to the variation in birefringence of the SHF and hence interference pattern shift of the Sagnac interferometer. A sensitivity of 86.8 pm/℃ is achieved when temperature changes between 20 ℃ and 80 ℃. It is about eight times of that of a normal fiber Bragg grating (FBG) sensor.

Colorization with depth perception for vehicular infrared image is implemented. We segment the vehicular infrared image into sky, tree and road classes using region growing method and then estimate the depth of each kind of scene. According to the depth information and prior knowledge of scenery colors, colors with depth perception are transferred to the infrared images. The experimental results show that the proposed method can colorize the infrared image with natural depth perception.

Multiple-beam Fourier telescope (MFT) has a unique advantage for high-speed imaging of moving object which is small and dim in deep space, but the key technology on optics, electricity, machinery and software limite the development of MFT. The frequency shift of every laser is anslysed according to the principle of MFT and Golomb ruler, and a suitable acousto-optical device has been designed. As a result, with the help of Golomb ruler, the maximum of relative frequency shift is 7.47 MHz, under 31 lasers, the aperture of device is 8 mm, and the minimum of diffraction efficiency is 0.9021, the requirement of MTF can be satisfied with all these index. Therefore, the frequency shift technology of MTF is possible.

Based on the analysis of the imaging process of optoelectronic imaging anti-ship missile, an image registration algorithm based on sensor parameters and region of interest (RDI) is proposed. Originally the distortion between infrared and visible images is affine. Firstly, by adjusting sensor parameters, the scaling change between images is eliminated and the affine transform is simplified into rigid transform. Then the ROI is got by locating the horizontal region, and the center of the target′s contour is computed by morphological edge detection and chosen as control point, which is used to eliminate the translational change between images and achieve complete alignment. Finally, the registration effect is assessed by using the rule of root mean square error. The simulation experiments convince that the algorithm is accurate and fast, and can meet the precision requirement for target recognition, providing a good way for solving the difficult registration problem of small target images with different sensors.

Infrared image of large field-of-view (FOV) has high resolution, so it is very difficult to process the image in real time by pixel. In order to solve this problem, a method of detection from coarse to fine is put forward to detect the small flying target in a special low-altitude background. We divide image into pieces and compute the entropy, so that the entropy′s segmentation can be performed, complete the background classification and acquire the target area, it′s coarse detection. Then according to top-hat filtering, the dim and small target is detected. The experimental result shows that this method can detect the dim and small target in large FOV more efficiently and accomplish real-time detection.

According to the principle of total internal reflection and autocollimator angle measurement method, accurate measurement of the prism refractive index is achieved. By the using of highly aligned semiconductor laser, the laser goes into interface of the prism and air. The curve of the prism′s reflected light versus the incident angle is obtained by rotating prism or changing the prism′s incident angle gradually. A step appears at the left side of the curve ending and its reflected light rapidly attenuates with the increasing of the incident angle, which is the angle of total reflection. The base angle of the prism is accurately measured by the double using of auto collimation angle measurement method. Refractive index of two pieces of different prism is measured by this method, respectively. The measuring accuracy is ±1.24×10-4.

According to the analysis on the system structure of the microwave instantaneous frequency measurement based on phase modulation, detailed structure simulation and analysis of device parameters are performed on Optisystem software. With different input carrier wavelengths, section measurement results are obtained. Within the measurement range of 6~18 GHz, the lowest error is 0.1 GHz. The unknown frequency is got from detecting the ratio of output power, and measurement errors of about 0.5 GHz, 0.2 GHz and 0.1 GHz are realized for the measurement ranges of 6~11 GHz, 11~15 GHz and 15~18 GHz, respectively.

A method using Michelson interferometer, polarization interferometry system and white-light vertical scanning system for measuring the retardation of wave plates (including the order of retardation) is presented. Two beams with the same polarization directions are introduced after a collimated white-light passes through the polarization interference system. Then the two beams are respectively reflected by two plane mirrors of the Michelson interferometer. As the moving mirror driven with piezoelectric transducer (PZT) scans vertically, three white-light interference packets are formed and are captured by a CCD camera. The retardation of wave plates can be calculated by the optical-path difference between the central packet and side packet. A multiple-order wave plate is tested by the white-light interference vertical scanning method, and the measured retardation (4268.1 nm) coincides with the that (4269.9 nm) measured by spectroscopic scanning method.

Cr,Tm,Ho:YAG laser system based on Q switching of LiNbO3 with Brewster angle cut ends is developed. The influence of the angle by which the LiNbO3 crystal is placed on the output energy and polarization properties at free running regime is measured. The experimental results indicate that when the LiNbO3 crystal is placed in the Brewster angle, the laser will achieve the highest efficiency. Furthermore, the output beam has the largest p component and the best linear polarization properties, which are beneficial to the Q switching of Cr,Tm,Ho:YAG laser. The output energy, pulse width and pulse profile of Cr,Tm,Ho:YAG laser at various lamp voltages at Q switching regime are investigated. The maximum pulse energy of 25 mJ and the minimum pulse width of 265 ns at the repetition rate of 2 Hz are achieved, and the peak power is up to 94.3 kW. The pulse profile presents nearly smooth Gaussian distribution.

In order to satisfy the need of multi-pass and multi-station laser processing, Nd:YAG pulsed laser is chosen as the light source and the laser double-pass time-sharing multiplexing system is developed. A concrete implementation scheme for time-sharing multiplexing is put forward, and in order to achieve time-sharing multiplexing beam splitting, controllable 30° revolving beam splitting device is designed, besides, a time-sharing multiplexing control circuit is designed to achieve real-time control of the device, and the system working time sequence is determined. In this way, time-sharing multiplexing and multi-pass output can be realized under the premise of not reducing the output power. Energy meter is used to collect data for calculating the light path coupling efficiency. The results of experiments show that when the current is 50 A and pulse width is 4 ms, the coupling efficiency of path A is 85.21% and that of path B is 85.23%, in the state of which the demand of multi-station processing can be met. And combined with practical applications, two splitting light paths are designed, one is used for welding and the other for melting and coating.

In the target area of large inertial confinement fusion (ICF) facility, the rectangular beams arrangement at the main amplifier output is mapped to the spherical-geometry beams configuration near the target chamber. The beams are imported into the final optical assemblies with special angles. The beam transport system is designed based on the beams arrangement. The beams arrangement should meet physical and optical requirements. At the same time, the construction cost and the maintenance performance of the beam transport system should be seriously considered. In larger ICF facility, the beams arrangement is much more complex with the increase of beam number. The beams arrangements of the large facilities in the world are analyzed. The relationships between the beams arrangement and the layout of beam transport system, the opto-mechanical design and the maintenance performance are discussed. Some advices of the beams arrangement are given for the ICF facility with much more multiple beams.

Transverse-flow CO2 laser is used to strengthen the NiAl/nano Al2O3 electroless composite plating by laser remelting. Then high-temperature oxidation resistance experiments at 800 ℃ of laser remelted coating are carried out. The surface profile, microstructure and high-temperature oxidation resistance of plated coatings before and after laser remelting are analyzed by energy dispersive X-ray spectrum (EDS), scanning electron microscopy (SEM) and X-ray diffractometry (XRD). The high-tempetature oxidation resistance of laser remelted coating is remarkably improved compared with the original composite plate and substrate. On the one hand, the intermetallics NiAl2O4 and Ni0.77AlFe0.23 of laser remelted coating contribute to enhance high-temperature oxidation resistance at 800 ℃; on the other hand, a dense and continuous oxidation film is formed on the coating surface after laser remelting.

For the p polarizations, the surface plasmon polaritons (SPPs) of form birefringence metal and regular materials are investigated. According to the biaxial anisotropy of the permittivity of the form birefringence metal and the dispersion relations of SPP, the characteristic lengths of SPP, including SPP wavelength, propagation distance of SPP and penetration depths of SPP in two media, are discussed in X direction and Y direction. In addition, the effects of three periodic structure parameters of form birefringence metal on the characteristic lengths of SPP are discussed. It is shown that the structure period in Y direction only controls the characteristic lengths of SPP in X direction, the structure period in X direction only affects the characteristic lengths of SPP in Y direction, and the radius of nanoholes adjusts the characteristic lengths of SPP in both X direction and Y direction.

The propagation of light waves in quasi-periodic photonic crystals based on the Thue-Morse sequence is investigated by the transfer matrix method. The linear transmission spectrum of such photonic structures exhibits a fractal nature of self-similar pattern, so as the electric field distribution. If the order number of Thue-Morse sequence is odd, the electric-field profile in the quasicrystal is asymmetric. In the case of Kerr nonlinearity, this will result in different bistability sensitive to the propagation direction. Under a certain condition, the light wave can unidirectionally transmit with external pump-assisting. This provides the realization of all-optical diode.

Quantization digit of voltage limits the choice scope of wave front phase, causes actual angle deviating from ideal angle, and further decreases steering accuracy. Steering accuracy is one of the most significant performance indexes of liquid-crystal phased array (LCPA). An optimization algorithm is proposed aiming at improving steering accuracy. The algorithm is based on optimization theory; it adopts method of pattern search to optimize objective using the way of adjusting voltage staircase. The influence of voltage quantization on steering accuracy is analyzed first, and then model of wave control is established. Last the decreasing of deviations between actual angle and ideal angle is taken as objective to correct corresponding voltage staircases using pattern search. Simulation results show that the algorithm can decrease normalized accuracy error from order of 100 to 10-3 in the range of scanning angles, which is remarkable.

The effect of structure period number on the transmission quality of one-dimensional photonic crystal with single-and double-barrier quantum well is studied with the transfer matrix method. The result shows that the transmission peaks of the photonic crystal with both single-barrier and double-barrier quantum well turn narrower with increase of the period number of well layer. So to speak, quality factors increase under this circumstance and the one of photonic crystal with double-barrier quantum well increases faster. Transmission peaks rapidly sharpen when the period number of barrier layer becomes greater. That is to say, quality factors rise quickly and the one of photonic crystal with double barrier quantum well rises fastest. The effect of the periodicity of barrier layer on the transmission quality is obviously stronger than the one of well layer. When the periodicity of barrier layer keeps increasing and reaches a certain value, the quality factor of transmission peaks at the double barrier well tends to be infinity. In other words, the transmission peaks become sharp to a certain frequency. These characteristics provide guidance for designing new quantum devices such as optical filter of high quality.

Three-dimensional (3D) shape measuring techniques, using a combination of grating projection and a most frequently used mathematical tool-Fourier fringe analysis, have been deeply researched and extensively appled. Such kind of techniques is based on the idea of projecting and superposing a carrier fringe pattern onto the surface of the tested object, and then reconstructing its corresponding 3D shape from the deformed fringe pattern modulated by the height of the tested object and captured by a camera from some other view direction. This paper mainly reviews the basic principles and typical applications of the combined technology based on grating projection and Fourier fringe analysis that we developed over past ten years. The fundamental concepts of time-average fringe method for vibration mode analysis and its experimental results are also presented. Lastly, the advantages and challenges of this technique and the current development of real-time measurement in this research field are described as a discussion and conclusion.

Femtosecond laser pulses can induce carrier excitation, relaxation and refractive index change via nonlinear interaction in transparent dielectrics, which then act as optical waveguide. The fabrication of active and passive optical waveguide devices by femtosecond laser has been extensively researched owing to its unrivaled highly-localized and three-dimensional machining capability. In this paper, three aspects of femtosecond laser-induced waveguide devices are introduced. The mechanisms of femtosecond laser-induced refractive-index change is discussed. Recent experimental progress regarding the fabrication waveguide is reviewed. At last, the future trends and application prospects of femtosecond laser-induced waveguide devices are analyzed.

Crossbar network is one of the most important and effective structures to achieve high-speed parallel optical processing in optical switching networks. As a non-blocking network, crossbar network is simple, easy to control, and suitable for forming optical switch matrix. We summarize and analyze crossbar optical switching networks on the recent development for more than 20 years, describe the various crossbar principles, structures and properties of optical switching networks, and analyze the crossbar key technologies for optical switching network.The recent development direction of optical interconnection network is to achieve integrated large-scale optical interconnection. It is predictable that optical interconnection network will become more practical and play an increasingly important role in its application areas.

The simulation of laser radar system has important values and wide application foreground. This paper focuses emphatically on the research advances of foreign typical imaging ladar simulation softwares, discusses their simulation principles, methods, functions and test validations and so on, and then summarizes the functions and meanings of laser radar modeling and simulation. At last this paper puts forward the development orientation. It can provide references for the next research thinking and methods.

Liquid crystal microlens array (LCMLA) is a new technology based on the micro-optics and liquid crystal technology. The operating principles, the research and development trend, and the challenges are reviewed.

The measurement methods of narrow linewidth lasers are reviewed. The basic principle of narrow linewidth laser measurement based on optical heterodyne method is introduced. The testing mechanisms of double-light-beam heterodyne and delayed self-heterodyne methods are described. For the systematic error frequently introduced in delayed zero frequency self-heterodyne method, source modulation and path modulation non-zero frequency self-heterodyne methods have been developed, and these improved methods have their advantages and disadvantages, respectively. Moreover, the new measurement methods of narrow linewidth lasers are summarized. The full spectrum of measurement methods of narrow linewidth lasers is shown, and it is seen that double-light-beam heterodyne and delayed self-heterodyne methods can find superiority for different conditions.

In recent 30 years, fiber optical rotary joints (FORJ) technology has made great progress. The mainly function and recent development of FORJs are reviewed. The principles and technologies of Dove prism, wave division multiplex (WDM) and K reflective mirror despunning are introduced. Property comparison of the three mentioned technologies are also presented. At last, the potential applications of FORJs are listed.

Since the first launch of hyperspectral imaging satellite on August 23,1997, space-borne hyperspectral imaging technology has been developed for 15 years. In these years, rapid progress was made in China. Before constructing the high resolution earth observing system, it is important to review the status of space-borne hyperspectral imaging technology in the past years. The developed country′s future plan should be of benefit to our space-borne strategy. Typical imaging spectrometers are summarized, application capabilities of space-borne hyperspectral imaging technology analyzed, and the prospect of hyperspectral imaging technology is presented. To realize wider swath and higher accuracy, technological innovation will occur for future civil space-borne hyperspectral imaging system. Higher spatial resolution, wider spectral range and rapid data processing technology will be expected for defense and security continuously.

Qualitative analysis and quantitative detection on the content of copper in the lake are implemented by laser induced breakdown spectroscopy. In the experiment, the spectral intensity value of Cu at 324.75 nm is measured in the concentration of 2~75 mg/L with laser energy of 120 mJ, delay time of 1.28 μs and repetition frequency of 1 Hz. Qualitative analysis is carried out on the characteristic spectral line of Cu, and the calibration curve of Cu about the concentration and spectral intensity, with the correlation coefficient R2=0.99, is obtained. The detection limit of Cu is 7.37 mg/L through the detection limit formula. In the end, the content of Cu in the lake is detected using the calibration curve and the result is 10 mg/L. The experiment proves that the heavy mental of Cu in water solution can be quickly detected by LIBS.

A CCD pulsed signal acquisition system for the spectral measurements in laser-induced breakdown spectroscopy (LIBS) is designed. We adopt a highly sensitive Sony ILX554B linear CCD as detector, and exploit a novel CCD driving method that can freely adjust the delay time relative to the laser pulse and the integration time of the photosensitive units in the CCD. By optimizing the delay time and the integration time, it can reduce the interference of the background emissions significantly and improve the sensitivity of LIBS. The LIBS signals of several kinds of samples under different delay times and integration time are measured, and it is shown that the system has a good performance in rapid analysis of LIBS, providing technical support to develop an inexpensive LIBS instrument.