The research focused on the effect of delay time in combined pulse laser machining on the material temperature field. Aiming at the parameter optimization of pulse laser machining aluminum alloy, the combined pulse laser model based on heat conduction equation was introduced. And the finite element analysis software, COMSOL Multiphysics, was also utilized in the research. Without considering the phase transition process of aluminum alloy, the results of the numerical simulation was shown in this paper. By the simulation study of aluminum alloy’s irradiation with combined pulse, the effect of the change in delay time of combined pulse on the temperature field of the aluminum alloy and simultaneously the quantized results under the specific laser spot conditions were obtained. Based on the results, several conclusions could be reached, the delay time could affect the rule of temperature changing with time. The reasonable delay time controlling would help improving the efficiency. In addition, when the condition of the laser pulse energy density is constant, the optimal delay time depends on pulse sequence.

The influence of different pressures, temperatures, scattering angles and incident wavelengths to the relative intensity of the Brillouin peaks to the Rayleigh peak and the Brillouin shift in the spontaneous Rayleigh-Brillouin scattering (SRBS) spectra of N₂ is analyzed by using the Tenti S6 model. A system for detecting the SRBS spectra of gas is also introduced in this paper. The SRBS spectra of N₂ at different pressures with the incident wavelength of 532nm, the temperature of 300K and the scattering angle of 90° have been measured, the experiment results are well agreed to the simulations.

Researching attenuation characteristic of UWB signals propagation in free-space is necessary for ultra-wideband (UWB) radio fuze optimized design. Research attenuation characteristic of UWB signals propagation in free space can be achieved by learning attenuation characteristic of radio waves propagation in free-space and UWB signal power spectral density. 50ps, 100ps and 200ps of pulse width UWB fuze transmission narrow pulse signal propagation in free-space are simulated and analyzed. The attenuation of UWB signals at 3m, 6m and 9m are contrasted. The simulation, analysis and contrast is theoretical basis of UWB radio fuze optimized design.

Good target detection and tracking technique is significantly meaningful to increase infrared target detection distance and enhance resolution capacity. For the target detection problem about infrared imagining, firstly, the basic principles of level set method and GAC model are is analyzed in great detail. Secondly, “convergent force” is added according to the defect that GAC model is stagnant outside the deep concave region and cannot reach deep concave edge to build the promoted GAC model. Lastly, the self-adaptive detection method in combination of Sobel operation and GAC model is put forward by combining the advantages that subject position of the target could be detected with Sobel operator and the continuous edge of the target could be obtained through GAC model. In order to verify the effectiveness of the model, the two groups of experiments are carried out by selecting the images under different noise effects. Besides, the comparative analysis is conducted with LBF and LIF models. The experimental result shows that target could be better locked through LIF and LBF algorithms for the slight noise effect. The accuracy of segmentation is above 0.8. However, as for the strong noise effect, the target and noise couldn’t be distinguished under the strong interference of GAC, LIF and LBF algorithms, thus lots of non-target parts are extracted during iterative process. The accuracy of segmentation is below 0.8. The accurate target position is extracted through the algorithm proposed in this paper. Besides, the accuracy of segmentation is above 0.8.

According to the characteristics of chaotic laser, which has ability of novel anti-jamming, high bandwidth and detecting distance of the movement target to the millimeter precision, a modeling method of using airborne chaotic laser system to detect distance of high remote targets is proposed for the first time. The characteristics of chaotic laser and principle of interferometry distance were analyzed and the model of airborne chaotic laser ranging is established. Meanwhile, the influence of detection accuracy, which inducted by the main peak width of chaotic laser and the jamming signal is analyzed. According to the results of simulation analysis, we can get conclusions that the main factors of affecting the distance measurement are transmitted power, receiving sensitivity, and various losses of transmission medium. Autocorrelation characteristic of chaotic signal can also affect the dynamic range of the whole system. The main peak width of chaotic laser is the main factor of influencing the accuracy of measurement. However, the jamming signal affect distance measuring range and accuracy of measurement little. Finally, the model’s effectiveness is proved by comparing the experience data and simulation data.

In the low cost laser tracking applications, the width of the laser echo pulses received by four-quadrant photodetector from an illuminated target are narrow, and are only a few hundred or dozens of nanoseconds. In order to obtain the peak of these narrow laser pulses of nS level, by using peak holding technique, a simplified transconductance peak holding circuit model is constructed, taking into account of low cost applications with large number of requirements. The key parameters of the transconductance peak holding circuit such as response time, droop rate and bandwidth are analyzed for narrow laser pulse signals. The transconductance peak holding circuit is designed using a low-cost integrated chip OPA615, then is simulated by the software PSpice tools. Finally, a circuit board is manufactured for further tests. The results show that: the bandwidth of the circuit is about 76.4 MHz, response time is about 7 ns, and droop rate is about 5.7 mV/μs. The peaks of narrow laser pulses are effectively acquired, meeting the needs for the subsequent low speed and low cost A/D converter.

In order to resolve the difficult problem of detection and identification of optical targets in complex background or in long-distance transmission, this paper mainly study the range profiles of “cat-eye” targets using bi-spectrum. For the problems of laser echo signal attenuation serious and low Signal-Noise Ratio (SNR), the multi-pulse laser signal echo signal detection algorithm which is based on high-order cumulant, filter processing and the accumulation of multi-pulse is proposed. This could improve the detection range effectively. In order to extract the stable characteristics of the one-dimensional range profile coming from the cat-eye targets, a method is proposed which extracts the bi-spectrum feature, and uses the singular value decomposition to simplify the calculation. Then, by extracting data samples of different distance, type and incidence angle, verify the stability of the eigenvector and effectiveness extracted by bi-spectrum.

Based on the physical meaning of the laser radar scattering cross section (LRCS), When the target is the standard target or the extension target, the LRCS analytical expressions and numerical expression are deduced. Based on the LRCS expression, Proposed a dual station visualization comparison measurement method, the purpose is to use a known radar cross section of the standard target, by the power detector, and CCD images obtained gray value, calculated the target's radar cross section. In the paper, we designed the optical emission system and the optical receiving system, then detected target backscatter light power, Sampled the target image, Using MATLAB calculate the power density ratio of test objectives and reference target., compared the measured data with the empirical data, verify the feasibility of the dual station visualization comparison measurement method.

Mature red blood cells (RBC) do not contain huge complex nuclei and organelles, makes them can be approximately regarded as homogeneous medium particles. To compute the radiation pressure force (RPF) exerted by multiple laser beams on this kind of arbitrary shaped homogenous nano-particles, a fast electromagnetic optics method is demonstrated. In general, based on the Maxwell’s equations, the matrix equation formed by the method of moment (MOM) has many right hand sides (RHS’s) corresponding to the different laser beams. In order to accelerate computing the matrix equation, the algorithm conducts low-rank decomposition on the excitation matrix consisting of all RHS’s to figure out the so-called skeleton laser beams by interpolative decomposition (ID). After the solutions corresponding to the skeletons are obtained, the desired responses can be reconstructed efficiently. Some numerical results are performed to validate the developed method.

The photoacoustic signals denoising of glucose is one of most important steps in the quality identification of the fruit because the real-time photoacoustic singals of glucose are easily interfered by all kinds of noises. To remove the noises and some useless information, an improved wavelet threshld function were proposed. Compared with the traditional wavelet hard and soft threshold functions, the improved wavelet threshold function can overcome the pseudo-oscillation effect of the denoised photoacoustic signals due to the continuity of the improved wavelet threshold function, and the error between the denoised signals and the original signals can be decreased. To validate the feasibility of the improved wavelet threshold function denoising, the denoising simulation experiments based on MATLAB programmimg were performed. In the simulation experiments, the standard test signal was used, and three different denoising methods were used and compared with the improved wavelet threshold function. The signal-to-noise ratio (SNR) and the root-mean-square error (RMSE) values were used to evaluate the performance of the improved wavelet threshold function denoising. The experimental results demonstrate that the SNR value of the improved wavelet threshold function is largest and the RMSE value is lest, which fully verifies that the improved wavelet threshold function denoising is feasible. Finally, the improved wavelet threshold function denoising was used to remove the noises of the photoacoustic signals of the glucose solutions. The denoising effect is also very good. Therefore, the improved wavelet threshold function denoising proposed by this paper, has a potential value in the field of denoising for the photoacoustic singals.

Laser machining is one of most widely used technologies nowadays and becoming a hot industry as well. At the same time, many kinds of carbon fiber material have been used in different area, such as sports products, transportation, microelectronic industry and so on. Moreover, there is lack of the combination research on the laser interaction with Carbon Fiber Reinforced Polymer (CFRP) material with simulation method. In this paper, the temperature status of long pulse laser interaction with CFRP will be simulated and discussed. Firstly, a laser thermal damage model has been built considering the heat conduction theory and thermal-elasto-plastic theory. Then using COMSOL Multiphysics software to build the geometric model and to simulate the mathematic results. Secondly, the functions of long pulse laser interaction with CFRP has been introduced. Material surface temperature increased by time during the laser irradiating time and the increasing speed is faster when the laser fluence is higher. Furthermore, the peak temperature of the center of material surface is increasing by enhanced the laser fluence when the pulse length is a constant value. In this condition, both the ablation depth and the Heat Affected Zone(HAZ) is larger when increased laser fluence. When keep the laser fluence as a constant value, the laser with shorter pulse length is more easier to make the CFRP to the vaporization material. Meanwhile, the HAZ is becoming larger when the pulse length is longer, and the thermal effect depth is as the same trend as the HAZ. As a result, when long pulse laser interaction with CFRP material, the thermal effect is the significant value to analysis the process, which is mostly effect by laser fluence and pulse length. For laser machining in different industries, the laser parameter choose should be different. The shorter pulse length laser is suitable for the laser machining which requires high accuracy, and the longer one is better for the deeper or larger ablation holes.

A coherence length tunable solid-state laser based on Fabry-Perot (F-P) etalon with high stability is constructed. Principles of the coherence length tuning method by rotating the F-P etalon are theoretically analyzed and experimentally verified. By using Nd:YAG as the gain medium, an all-solid-state 1064 nm laser with 375 mW output power, 0.37% high power stability(RMS), high beam quality, and tunable coherence lengths from 9.37 cm to 20.05 cm is achieved. This method could be extended to multiband center wavelengths for their tuning of coherence length.

There are contradictions among speediness, anti-disturbance performance, and steady-state accuracy caused by traditional PID controller in the existing light source systems of thermal frequency stabilizing laser with double longitudinal modes. In this paper, a new kind of fuzzy adaptive PID controller was designed by combining fuzzy PID control technology and expert system to make frequency stabilizing system obtain the optimal performance. The experiments show that the frequency stability of the designed PID controller is similar to the existing PID controller (the magnitude of frequency stability is less than 10^-9 in constant temperature and 10^-7 in open air). But the preheating time is shortened obviously (from 10 minutes to 5 minutes) and the anti-disturbance capability is improved significantly (the recovery time needed after strong interference is reduced from 1 minute to 10 seconds).

Platform screen door can not only prevent the passengers fell or jumped the track danger, to passengers bring comfortable waiting environment, but also has the function of environmental protection and energy saving. But platform screen door and train the full-length gap region is insecure in the system design of a hidden, such as passengers for some reason (grab the train) in the interstitial region retention, is sandwiched between the intercity safety door and the door, and such as the region lacks security detection and alarm system, once the passengers in the gap region retention (caught), bring more serious threat to the safety of passengers and traffic safety. This paper from the point of view of the design presents the physical, infrared, laser three safety protection device setting schemes. Domestic intelligence of between rail transit shield door and train security clearance processing used is screen door system standard configuration, the obstacle detection function for avoid passengers stranded in the clearance has strong prevention function. Laser detection research and development projects can access to prevent shield door and train gap clamp safety measures. Rail safety protection method are studied applying laser detection technique. According to the laser reflection equation of foreign body, the characteristics of laser detection of foreign bodies are given in theory. By using statistical analysis method, the workflow of laser detection system is established. On this basis, protection methods is proposed. Finally the simulation and test results show that the laser detection technology in the rail traffic safety protection reliability and stability, And the future laser detection technology in is discussed the development of rail transit.

In order to obtain the velocity with high dependability at extreme combustion condition, a 2-D interferometric Rayleigh scattering (IRS) velocimetry based on detecting the Doppler frequency shift of molecular scattering with Fabry–Perot etalon was developed. The 2-D IRS measurement system was set up with a multi-beam probe laser, aspherical lens collection optics, and a solid Fabry-Perot etalon. A multi-beam probe laser with 0.5mm intervals was formed by collimating a laser sheet passing through a cylindrical microlens arrays. The aspherical lens was used to enhance the intensity of Rayleigh scattering signal. The 2-D velocity results of a Mach 1.5 air flow were obtained. The velocity in the flow center is about 450 m/s. The reconstructed results are in accordance with the characteristic of flow, which indicates the validity of this technique.

Atmosphere laser communication takes advantage of laser as the carrier transmitting the voice, data, and image information in the atmosphere. Because of its high reliability, strong anti-interference ability, the advantages of easy installation, it has great potential and development space in the communications field. In the process of establish communication, the capture, targeting and tracking of the communication signal is the key technology. This paper introduce a method of targeting the signal spot in the process of atmosphere laser communication, which through the way of making analog signal addition and subtraction directly and normalized to obtain the target azimuth information to drive the servo system to achieve precise alignment of tracking.

The research focuses on measuring the influence of angel on wedge waves propagating along cylinder wedge tip and its characteristic of dispersion by using the laser ultrasound technique. The wedge waveguide models with different angle were built by using finite element method (FEM). The dispersion curves were obtained by using 2D Fourier transformation method. Multiple mode wedge waves were observed, which was well agreed with the results estimated from Lagasse’s empirical formula. We had established cylinder wedge with radius of 3mm and angle of 10°, 20°, 30°, 40‡, 50°, 60°, 70°, and 80°, respectively. It was found that radius caused abnormal dispersion to the mode of cylinder wedge with small angle and normal dispersion to the mode of cylinder wedge with big angle.

Stainless steel railway vehicles with so many advantages, such as lightweight, antirust, low cost of maintenance and simple manufacturing process, so the production of high level stainless steel railway vehicles has become the development strategy of European, American and other developed nations. The current stainless steel railway vehicles body and structure are usually assembled by resistance spot welding process. The weak points of this process are the poor surface quality and bad airtight due to the pressure of electrodes. In this study, the partial penetration lap laser welding process was investigated to resolve the problems, by controlling the laser to stop at the second plate in the appropriate penetration. The lap laser welding joint of stainless steel railway vehicle car body with partial penetration has higher strength and surface quality than those of resistance spot welding joint. The biggest problem of lap laser welding technology is to find the balance of the strength and surface quality with different penetrations. The mechanism of overlap laser welding of stainless steel, mechanical tests, microstructure analysis, the optimization of welding parameters, analysis of fatigue performance, the design of laser welding stainless steel railway vehicles structure and the development of non-destructive testing technology were systematically studied before lap laser welding process to be applied in manufacture of railway vehicles. The results of the experiments and study show that high-quality surface state and higher fatigue strength can be achieved by the partial penetration overlap laser welding of the side panel structure, and the structure strength of the car body can be higher than the requirements of En12663, the standard of structural requirements of railway vehicles bodies. Our company has produced the stainless steel subway and high way railway vehicles by using overlap laser welding technology. The application of lap laser welding will be a big change of railway vehicles manufacturing technology.

The cat-eye effect echo of optical system can be detected based on CCD, but the detection range is limited within several kilometers. In order to achieve long-range even ultra-long-range detection, it ought to select APD as detector because of the high sensitivity of APD. The detection system of cat-eye effect echo based on unit APD is designed in paper. The implementation scheme and key technology of the detection system is presented. The detection performances of the detection system including detection range, detection probability and false alarm probability are modeled. Based on the model, the performances of the detection system are analyzed using typical parameters. The results of numerical calculation show that the echo signal-to-noise ratio is greater than six, the detection probability is greater than 99.9% and the false alarm probability is less tan 0.1% within 20 km detection range. In order to verify the detection effect, we built the experimental platform of detection system according to the design scheme and carry out the field experiments. The experimental results agree well with the results of numerical calculation, which prove that the detection system based on the unit APD is feasible to realize remote detection for cat-eye effect echo.

This paper investigates optical properties of few-mode fiber with non-uniform refractive index, namely: the few mode fiber with U-shape refractive index and the two-mode and four-mode few-mode fiber with bent radius. Finite element method is used to analyze the mode distributions based on their non-uniform refractive index. Effective mode control can be achieved through these few mode fibers to achieve vector beam generation. Finally, reflection spectra of a few-mode fiber Bragg grating are calculated theoretically and then measured under different bending conditions. Experimental results are in good accordance with the theoretical ones. These few mode fibers show potential applications in generation of cylindrical vector beam both for optical lasing and sensing systems.

A new subminiature endoscope which used for reconnaissance and diagnosis has been designed. This subminiature endoscope is designed based on imaging fiber bundle and consist of the front object lens whose aperture is only 0.5mm, imaging fiber bundle and the post coupling lens. It realized by using subminiature optical systems . The FOV(field of view) and the focal length of the front object lens are 50° and 0.59mm. And the object distance, F number and detected imaging high of the front object lens are 3mm, 6 and 0.5mm. The total number of the imaging fiber bundle are 10000 and it’s pixel cell size is 5 μm. The effective aperture of the imaging fiber bundle is 0.46mm. The post coupling lens has a reduction ratio of 1.73. It’s object distance and imaging height are 5mm and 0.8mm. The Numerical Aperture (NA) of the front object lens, imaging fiber bundle and the post coupling lens are matching will. The coupling efficiency of the imaging fiber bundle is above 93% and the system’s design result can meet the need of the limit resolution of the imaging fiber. This kind of the fiber endoscope has the peculiarity of wide FOV, fine imaging quality, compact configuration, low finished cost and etc. It is meaningful to realize the objective of miniaturization, batch-type production and high imaging quality of the endoscope.

Laser positioning technology in the world has a very broad application prospects. With the development of technology and enhancement of productivity, the technology of positioning accuracy and the detection region also need to improve. There are key factors for laser positioning system, including performance of photosensitive devices, localization algorithm and signal processing circuitry, which are important in determining the performance advantages and disadvantages. Therefore, we need to study in-depth research and improvement to enhance the overall performance of the detector. In this paper, after analyzing the principle of mainstream photo-sensitive induction device, we focus on the current and various positioning algorithms which are widely used. Then use simulation to compare the advantages and disadvantages of each method. Based detector probe in the actual working conditions, we analyze the reasons for the differences in the measurement detector sensitivity, linearity, etc., and provide noise and uniformity correction algorithm while improving on the previous probe calibration method. According to the distribution of the incident light energy, we improve the mathematical model of the original description of the received light energy in each quadrant. Based on the Gaussian distribution of light energy, light intensity correction algorithm is proposed in order to meet the needs of the actual probe. Based on the selected four-quadrant detector APD, we design and build a complete laser positioning system. At last, we design and build the experimental system which can be used to test the main parameters including measurement accuracy and response range of the four-quadrant detector, so the laser positioning system has been tested and verify the feasibility of the system. This paper has mainly innovation in the localization algorithm on the detector.

In the experiment of researching the nanometer laser interferometer, our design of laser interferometer circuit system is up to the wireless communication technique of the 802.15.4 IEEE standard, and we use the RF TI provided by Basic to receive the data on speed control system software. The system’s hardware is connected with control module and the DC motor. However, in the experiment, we found that single chip microcomputer control module is very difficult to drive the DC motor directly. The reason is that the DC motor's starting and braking current is larger than the causing current of the single chip microcomputer control module. In order to solve this problem, we add a driving module that control board can transmit PWM wave signal through I/O port to drive the DC motor, the driving circuit board can come true the function of the DC motor’s positive and reversal rotation and speed adjustment. In many various driving module, the L298N module’s integrated level is higher compared with other driver module. The L298N model is easy to control, it not only can control the DC motor, but also achieve motor speed control by modulating PWM wave that the control panel output. It also has the over-current protection function, when the motor lock, the L298N model can protect circuit and motor. So we use the driver module based on L298N to drive the DC motor. It is concluded that the L298N driver circuit module plays a very important role in the process of driving the DC motor in the DC motor speed control system.

We present a system to measure objective backscattering properties at 2.52 terahertz (THz). The optical setup combining 90° off-axis parabolic mirrors with 15° off-axis parabolic mirror decreases the size of the system and then realizes its compact structure. The calibration object, a conducting sphere with a diameter of 50 mm, was introduced to eliminate the influence of the instability of THz radiation and the background noise on measurement results. The lock-in amplifier was adopted to enhance the signal-to-noise ratio (SNR) and then make it possible to observe delicate backscattering behaviors on the surface of the object. Backscattering properties of four scale models were measured in this paper. Experimental results indicate that the maximal error of our system is less than 1 dB, paving the way for practical measurements of objective backscattering properties at THz frequencies.

With the development of terahertz technology and increasing studies on terahertz target scattering properties, research on terahertz target scattering properties measurements attracts more and more attention. In this paper, to solve problems in the detection process, we design a controlling software for Continuous-Wave (CW) terahertz target scattering properties measurements. The software is designed and programmed based on LabVIEW. The software controls the whole system, involving the switch between the target and the calibration target, the rotation of target, collection, display and storage of the initial data and display, storage of the data after the calibration process. The experimental results show that the software can accomplish the expected requirement, enhance the speed of scattering properties measurements and reduce operation errors.

Calculating radar cross section (RCS) of complex conductive targets is of great significance to design highly precise radar system, recognize targets and so on. This paper simulates complex objects with a periodic array of cylinders, and mainly focuses researches on the impacts on RCS by number, spacing and size of cylinders. The experimental results show that the biggest backward scattering RCSs of two-body to five-body cylinders were 0.0334sm, 0.0750sm, 0.1334sm and 0.2084 sm.

Holographic display has been considered as a promising display technology. Currently, low-speed generation of holograms with big holographic data is one of crucial bottlenecks for three dimensional (3D) dynamic holographic display. To solve this problem, the acceleration method computation platform is presented based on look-up table point source method. The computer generated holograms (CGHs) acquisition is sped up by offline file loading and inline calculation optimization, where a pure phase CGH with gigabyte data is encoded to record an object with 10 MB sampling data. Both numerical simulation and optical experiment demonstrate that the CGHs with 1920×1080 resolution by the proposed method can be applied to the 3D objects reconstruction with high quality successfully. It is believed that the CGHs with huge data can be generated by the proposed method with high speed for 3D dynamic holographic display in near future.

According to the requirement of the long range detection of the circumferential detection system of the laser fuze, a hybrid modulated pulsed laser driving power supplying for APD avalanche photodiode is designed. The working principle of the laser circumferential detection system is analyzed, and the APD is selected as the photoelectric detector according to the measurement equation of the circumferential detection system. According to the different kinds of APD requirements for high voltage power supply, the principle of boost converter is analyzed. By using PWM and PFM hybrid modulation type power supply technology, PWM modulation is applied in low rising voltage. When the voltage is required to achieve more than 100V, PFM mode boost is chosen. Simulation of the output voltages which are 85V and 200V of the two modes respectively is made. The PCB circuit board is processed to verify the experiment. The experimental results show that the hybrid modulation pulse laser drive power supply can meet the requirements of all kinds of APD power supply. The circuit board can be used in the detection of laser fuze with different target distance, and has wide application prospect.

According to the problem of the high-precision ranging in the circumferential scanning probe laser proximity fuze, a new type of pulsed laser ranging system has been designed. The laser transmitting module, laser receiving module and ranging processing module have been designed respectively. The factors affecting the ranging accuracy are discussed. And the method of improving the ranging accuracy is studied. The high-precision ranging system adopts the general high performance microprocessor C8051FXXX as the core. And the time interval measurement chip TDC-GP21 was used to implement the system. A PCB circuit board was processed to carry on the experiment. The results of the experiment prove that a centimeter level accuracy ranging system has been achieved. The works can offer reference for ranging system design of the circumferential scanning probe laser proximity fuze.

Aiming at the difficult problem of high precision frequency stabilization of semiconductor laser diode, the laser frequency control is realized through the design of the semiconductor drive system. Above all, the relationship between the emission frequency and the temperature of LD is derived theoretically. Then the temperature corresponding to the stable frequency is obtained. According to the desired temperature stability of LD, temperature control system is designed, which is composed of a temperature setting circuit, temperature gathering circuit, the temperature display circuit, analog PID control circuit and a semiconductor refrigerator control circuit module. By sampling technology, voltage of platinum resistance is acquired, and the converted temperature is display on liquid crystal display. PID analog control circuit controls speed stability and precision of temperature control. The constant current source circuit is designed to provide the reference voltage by a voltage stabilizing chip, which is buffered by an operational amplifier. It is connected with the MOSFET to drive the semiconductor laser to provide stable current for the semiconductor laser. PCB circuit board was finished and the experimental was justified. The experimental results show that: the design of the temperature control system could achieve the goal of temperature monitoring. Meanwhile, temperature can be stabilized at 40°C ± 0.1°C. The output voltage of the constant current source is 2 V. The current is 35 mA.

The existence of mode deflection angle in the cylindrical resonator gyroscope (CRG) leads to the signal drift on the detecting nodes of the gyro vibration and significantly decreases the performance of the CRG. Measuring the mode deflection angle efficiently is the foundation of tuning for the imperfect cylindrical shell resonator. In this paper, an optical method based on the measuring gyroscopic resonator’s vibration amplitude with the laser Doppler vibrometer and an electrical method based on measuring the output voltage of the electrodes on the resonator are both presented to measure the mode deflection angle. Comparative experiments were implemented to verify the methodology and the results show that both of the two methods could recognize the mode deflection angle efficiently. The precision of the optical method relies on the number and position of testing points distributed on the resonator. The electrical method with simple circuit shows high accuracy of measuring in a less time compared to the optical method and its error source arises from the influence of circuit noise as well as the inconsistent distribution of the piezoelectric electrodes.

Nowadays the technology of laser positioning based on four-quadrant detector has the wide scope of the study and application areas. The main principle of laser positioning is that by capturing the projection of the laser spot on the photosensitive surface of the detector, and then calculating the output signal from the detector to obtain the coordinates of the spot on the photosensitive surface of the detector, the coordinate information of the laser spot in the space with respect to detector system which reflects the spatial position of the target object is calculated effectively. Given the extensive application of FPGA technology and the pseudo-random sequence has the similar correlation of white noise, the measurement process of the interference, noise has little effect on the correlation peak. In order to improve anti-jamming capability of the guided missile in tracking process, when the laser pulse emission, the laser pulse period is pseudo-random encoded which maintains in the range of 40ms-65ms so that people of interfering can’t find the exact real laser pulse. Also, because the receiver knows the way to solve the pseudo-random code, when the receiver receives two consecutive laser pulses, the laser pulse period can be decoded successfully. In the FPGA hardware implementation process, around each laser pulse arrival time, the receiver can open a wave door to get location information contained the true signal. Taking into account the first two consecutive pulses received have been disturbed, so after receiving the first laser pulse, it receives all the laser pulse in the next 40ms-65ms to obtain the corresponding pseudo-random code.

The most important part of composite insulator is the joint of the composite rod and the metal end-fitting because most of mechanical faults take place here. Thus it is necessary to on-line monitoring of the joints. This paper theoretically analyzes the response behavior of the embedded fiber Bragg grating (FBG) in the joint based on our preliminary analysis of the stress distribution of the composite rod. Comprehensive considering the thermal stress and the material thermal coefficient, the reflection spectrum of FBG embedded in three typical locations is simulated. The simulation result shows that the wavelength shift of the FBG embedded in the joint is about 180pm larger than those embedded out of joint when the temperature rises 10°C. This result has the directive significance for the embedding position and the embedded way. It can be used to monitor the mechanical strength changing with temperature, to improve the manufacture technology of the joint, and to detect the change of electrical property.

The effect on operating distance by deviation between axis of emitting and receiving in turbulent atmosphere was analyzed in the paper, with the premise that the axis of emitting and sighting were parallel. First the model of operating distance with the deviation between axis of emitting and receiving was found. The facula center of emitting and the receiving was not coincidence but had displacement. So when calculating the laser reflectance power, the area of reflectance target was not the area of target, but the intersection parts of target, laser facula and the receiving field. Then the effect on laser facula by atmospheric turbulence was supplied. The laser facula was broken and the center was dispersion which would effect the operating distance. With the model of operating distance, the operating distance varying with the deviation angle between axis of emitting and receiving was discussed. In this session, the tables that the operating distance varying with the deviation angle were obtained with the premise that the laser facula distribution was Gaussian distribution and transmitting in turbulent atmosphere. By contrasting the tables, it could be showed that the operating distance was badly effected by the visibility and varying with the deviation angle when the laser facula was Gaussian distribution or transmitting in turbulent atmosphere.

The 248 nm excimer laser etching characteristic of alumina ceramic and sapphire had been studied using different laser fluence and different number of pulses. And the interaction mechanism of 248 nm excimer laser with alumina ceramic and sapphire had been analyzed. The results showed that when the laser fluence was less than 8 J/cm², the etching depth of alumina ceramic and sapphire were increased with the increase of laser fluence and number of pulses. At the high number pulses and high-energy, the surface of the sapphire had no obvious melting phenomenon, and the alumina ceramic appeared obvious melting phenomenon. The interaction mechanism of excimer laser with alumina ceramics and sapphire was mainly two-photon absorption. But because of the existence of impurities and defects, the coupling between the laser radiation and ceramic and sapphire was strong, and the thermal evaporation mechanism was also obvious.

It is difficult to detect the elastic deformation on the metal surface induced by nanosecond laser pulse. Optical fiber sensor system is suitable for detecting the elastic deformation, which has many advantages such as the high sensitivity, fast speed (GHz), non-contact, non-loss and point-measurement. We set up the measuring system to analyze the deformation mechanism firstly. Then, the elastic deformation on the metal surface was investigated. The relation between the shock-wave and elastic deformation was analyzed. The result of the present work implicated that as the nanosecond laser pulse radiated to the metal surface, elastic deformation had a delay time which was around 320ns. And the deformation presented the damped oscillation law. The data of laser-induced plasma shock wave were fitted and the fitting degree was 97.696%.The variation law of laser-induced plasma shock-wave was obtained. These results helped to make the laser removal applied to the manufacturing technique better.

We demonstrate an ultra-narrow-band mode-selection method based on a hybrid-microsphere-cavity which consists of a coated silica microsphere. Optical field distribution and narrow-band transmission spectrum of the whispering gallery modes (WGM) are investigated by finite-difference time-domain method. WGM transmission spectra are measured for microsphere and tapered fibers with different diameters. A high refractive index layer coated on the microsphere-cavity make the Q factor increased, the transmission spectrum bandwidth compressed and the side-mode suppression ratio increased. Parameters of the hybrid-microsphere-cavity, namely, the coated shell thickness and its refractive index are optimized under different excitation light source as to investigate the whispering-gallery-modes’ transmission spectrum. The 3dB bandwidth of the proposed filter can be less than MHz which will have great potential for applications in all-optical sensing and communication systems.

In the spatial coherent optical communication, after long distance transmission, the receiver needs to detect and extract the weak signal, and the balanced detection technology is the key technology in the coherent detection. Using balanced detection technology, not only can further improve the receiving sensitivity of coherent optical detection, but also can suppress the common mode intensity noise, so as to improve the output signal to noise ratio of the system. But the problems are (1) due to external causes (polarization control, input optical power loss error, atmospheric turbulence caused by decay, and so on),at both ends of the balanced detector’s input signal can not keep consistent (2) two arms of balanced detector electronic devices (including photodiode and amplifier electronic components) are difficult to achieve perfectly matched. The paper is based on the principle of coherent optical detection, firstly, the advantage of balanced detection compared to single detection is detailed analysis, it is shown that balanced detector used in coherent optical communication system and with the improvement of communication rate, this advantage will more obvious. The theoretical and experimental results have verified several important factors that affect the efficiency of coherent balanced detection, namely, the consistency of the detection response, the atmospheric turbulence and the tracking jitter. It is of reference significant to study the balance detection technology in the spatial coherent optical communication.

Taking the one-dimensional Laser Doppler Velocimeter (LDV) and a certain type of Laser Gyro Strapdown Inertial Navigation System (SINS) developed our staff room for object, the paper verifies that dynamic calibration technique can be achieved by SINS/LDV integrated system on the basis of the analysis of the software and hardware conditions. Extended Kalman filter states of SINS/LDV integrated system were chosen based on the error models of SINS and LDV. Using the difference of the output speed of the SINS and LDV as measurement, the error of bias and scale factor of the integrated navigation system are estimated effectively by setting up a reasonable calibration path. The effectiveness of the algorithm is further verified through the vehicular experiments. The results of experiments show that the dynamic calibration technique can be achieved through SINS/LDV integrated system and ensure the maneuverability of terrestrial inertial navigation system. The estimate of LDV scale factor is about 0.003%. The estimate error of accelerometer bias no more than 13μg. The estimate error of gyroscope drift no more than 1.7×10^-3°/h. The yaw angle error is less than 0.19 ' within 20min.

It is well known that laser possesses high brightness, high coherence, good directivity and other unique properties. In many practical applications, it is necessary to get small light spot in intermediate and long distance. Intermediate and long distance laser measurement demands to minimize the spot radius in order to improve the spatial resolution of the system and signal quality. Therefore, the study of Gaussian beam focusing property has high value for practical applications. In order to achieve intermediate and long distance laser measurement, this paper studies the method to adjust Gaussian beam spot diameter within a certain range after a near-field optical system transformation to improve the signal quality. Based on the fundamental characteristics of the Gaussian beam, this paper deduces the theoretical formula for the position and radius of the Gaussian beam waist and measures them by means of the CCD method. Then Matlab is used to simulate the spot diameter in the far field, and by combining numerical simulation results as well as optimizing the structure of the actual optical system, we make the light spot diameter in the target area fit the requirements of the laser velocimeter in intermediate and long distance measurement.

In this paper, the near-field optical properties of nanoparticles, which are deposited on Titanium (Ti) substrate and irradiated by laser pulses with wavelength ranging from 0.4 nm to 1.2 nm, are presented by using numerical simulations. Considering the near-field electric intensity distribution, the enhancement factor (E/E₀)² and the peak enhancement value (E_max/E₀)², we compared the difference between gold particle with 200 nm diameter and SiO₂ particle with 2μm diameter. It is found out that, the intensity distribution around the contact point between particles and Ti substrate shows as an annular. The enhancement factor generated by 200 nm gold particle is over 10 times larger than 2 μm SiO₂ particle after irradiated by incident light with the same wavelength. In experiment section, using 200 nm diameter gold particles, we fabricated nanoholes on Ti-6Al-4V surface with diameter about 170 nm when laser pulse energy was set as 0.354 J/cm². The diameter of nanoholes is corresponding to the previous simulation results in this paper.

Narrow pulse laser ranging achieves long-range target detection using laser pulse with low divergent beams. Pulse laser ranging is widely used in military, industrial, civil, engineering and transportation field. In this paper, an improved narrow pulse laser ranging algorithm is studied based on the high speed sampling. Firstly, theoretical simulation models have been built and analyzed including the laser emission and pulse laser ranging algorithm. An improved pulse ranging algorithm is developed. This new algorithm combines the matched filter algorithm and the constant fraction discrimination (CFD) algorithm. After the algorithm simulation, a laser ranging hardware system is set up to implement the improved algorithm. The laser ranging hardware system includes a laser diode, a laser detector and a high sample rate data logging circuit. Subsequently, using Verilog HDL language, the improved algorithm is implemented in the FPGA chip based on fusion of the matched filter algorithm and the CFD algorithm. Finally, the laser ranging experiment is carried out to test the improved algorithm ranging performance comparing to the matched filter algorithm and the CFD algorithm using the laser ranging hardware system. The test analysis result demonstrates that the laser ranging hardware system realized the high speed processing and high speed sampling data transmission. The algorithm analysis result presents that the improved algorithm achieves 0.3m distance ranging precision. The improved algorithm analysis result meets the expected effect, which is consistent with the theoretical simulation.

The picosecond laser has ultrashort pulse and superstrong peak power, which make it being focused on and applied in the micro-nanoscale fabrication field. Silicone elastomer PDMS is a typical antifouling material which can desorb defacement, using picosecond laser etching the surface through the way of galvanometer scanning in order to obtain a surface with micro-nano texture. The article studied the relationship between process parameters such as the power density, the scanning rate and the appearance of etched groove respectively, especially the width and depth of the groove. The results show that : for single marking, with the raise of the laser power density I, the depth of the groove increases, the inclination angle of the side wall is reduced. In another time, with the increase of the scanning rate v ,the depth of the groove decreases gradually and the surface morphology cannot be seen clearly. For multiple marking, the depth of the groove shown a falling slope from big to small with the increase of marking number. Finally,we got a path to optimize the process parameters to obtain a surface with micro-nano structures. After testing the surface contact angle, we found that the surface contact angle increased from 113° to 152°,which reached the level of superhydrophobic surface.

In this paper, the current technologies in full colour 3D printing technology were introduced. A framework of colour image reproduction process for 3D colour printing is proposed. A special focus was put on colour management for 3D printed objects. Two approaches, colorimetric colour reproduction and spectral based colour reproduction are proposed in order to faithfully reproduce colours in 3D objects. Two key studies, colour reproduction for soft tissue prostheses and colour uniformity correction across different orientations are described subsequently. Results are clear shown that applying proposed colour image reproduction framework, performance of colour reproduction can be significantly enhanced. With post colour corrections, a further improvement in colour process are achieved for 3D printed objects.

technology. Laser one-dimensional range profile can reflect the characteristics of the target shape and surface material. These techniques were motivated by applications of laser radar to target discrimination in ballistic missile defense. The radar equation of pulse laser about cone is given in this paper. This paper demonstrates the analytical model of laser one-dimensional range profile of cone based on the radar equation of the pulse laser. Simulations results of laser one-dimensional range profiles of some cones are given. Laser one-dimensional range profiles of cone, whose surface material with diffuse lambertian reflectance, is given in this paper. Laser one-dimensional range profiles of cone, whose surface mater with diffuse materials whose retroreflectance can be modeled closely with an exponential term that decays with increasing incidence angles, is given in this paper. Laser one-dimensional range profiles of different pulse width of cone is given in this paper. The influences of surface material, pulse width, attitude on the one-dimensional range are analyzed. The laser two-dimensional range profile is two-dimensional scattering imaging of pulse laser of target. The two-dimensional range profile of roughness target can provide range resolved information. An analytical model of two-dimensional laser range profile of cone is proposed. The simulations of two-dimensional laser range profiles of some cones are given. Laser two-dimensional range profiles of cone, whose surface mater with diffuse lambertian reflectance, is given in this paper. Laser two-dimensional range profiles of cone, whose surface mater with diffuse materials whose retroreflectance can be modeled closely with an exponential term that decays with increasing incidence angles, is given in this paper. The influence of pulse width, surface material on laser two-dimensional range profile is analyzed. Laser one-dimensional range profile and laser two-dimensional range profile are called as laser range profile (LRP).

In recent years, with the rapid development of digital chip, high speed sampling rate analog to digital conversion chip can be used to sample narrow laser pulse echo. Moreover, high speed processor is widely applied to achieve digital laser echo signal processing algorithm. The development of digital chip greatly improved the laser ranging detection accuracy. High speed sampling and processing circuit used in the laser ranging detection system has gradually been a research hotspot. In this paper, a pulse laser echo data logging and digital signal processing circuit system is studied based on the high speed sampling. This circuit consists of two parts: the pulse laser echo data processing circuit and the data transmission circuit. The pulse laser echo data processing circuit includes a laser diode, a laser detector and a high sample rate data logging circuit. The data transmission circuit receives the processed data from the pulse laser echo data processing circuit. The sample data is transmitted to the computer through USB2.0 interface. Finally, a PC interface is designed using C# language, in which the sampling laser pulse echo signal is demonstrated and the processed laser pulse is plotted. Finally, the laser ranging experiment is carried out to test the pulse laser echo data logging and digital signal processing circuit system. The experiment result demonstrates that the laser ranging hardware system achieved high speed data logging, high speed processing and high speed sampling data transmission.

This PDF file contains the front matter associated with SPIE Proceedings Volume 10153 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.