Journals >Infrared and Laser Engineering
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2023
Volume: 52 Issue 1
30 Article(s)
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Atmospheric Optics
Influence of atmospheric models on the aerosol optical parameters inversion and classification
Yuanzu Wang, Dongsong Sun, Yuli Han, Jun Zheng, and Yiming Zhao
Aerosols have a significant impact on the global ecosystem, material cycle, so it is important to study the accuracy of basic data such as aerosol optical parameters. Using the data from four observing stations (Potenza, Leipzig, Lille, Evora) of the European Aerosol Research Lidar Network during two intensive measuremAerosols have a significant impact on the global ecosystem, material cycle, so it is important to study the accuracy of basic data such as aerosol optical parameters. Using the data from four observing stations (Potenza, Leipzig, Lille, Evora) of the European Aerosol Research Lidar Network during two intensive measurement campaigns, the effects of temperature and pressure profiles provided by different atmospheric models on the inversion of aerosol optical parameters (extinction and backscatter coefficients) and aerosol classification are analyzed. The results show that: different atmoshpere models have an influence on the retrieval results of aerosol optical parameters, resulting in deviations in the calculation results, more influence can be found from the aerosol extinction coefficients obtained by the Raman method, with the maximum deviation ~20% at both 355 nm and 532 nm. Atmosphere aerosol concentration can also affect the retrieval results of aerosol optical parameter with different models and vary with the wavelength of observation. In addition, different models can influence the retrieval results of the aerosol lidar ratio and Ångström exponent, which are related to aerosol types, and ultimately affect the aerosol classification. The results are significant for revealing the importance of the selection of atmospheric models in the retrieval of aerosol optical parameters, for aerosol classification and related research in atmospheric science..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220262 (2023)
Image Processing
Single-image super-resolution reconstruction for continuous-wave terahertz imaging systems
Huan Wang, Liying Lang, Yajun Pang, Lei Zhang, Wei Zheng, and Sixing Xi
To address the problem that existing terahertz imaging systems require complex and expensive hardware equipment, a continuous-wave terahertz imaging system based on single-image super-resolution reconstruction is designed to reduce equipment complexity and hardware cost. By preprocessing the terahertz images generated To address the problem that existing terahertz imaging systems require complex and expensive hardware equipment, a continuous-wave terahertz imaging system based on single-image super-resolution reconstruction is designed to reduce equipment complexity and hardware cost. By preprocessing the terahertz images generated by this imaging system in two dimensions, the occupied memory of image processing is reduced and the speed of subsequent processing is increased. A restricted-contrast adaptive histogram equalization algorithm is introduced for sub-regional contrast enhancement of terahertz images to effectively solve the problem of low contrast of terahertz images. The super-resolution reconstruction of terahertz images is achieved by using sparse representation and dictionary learning, and the algorithm of inverse cosecant fitted with Newtonian smoothing zero parity is proposed to solve the zero-norm optimization problem and improve the reconstruction accuracy. By performing super-resolution reconstruction of single terahertz images acquired by this imaging system, the algorithm improves 3.232 in edge intensity and 0.300 in mean gradient comparison, which verifies the effectiveness and superiority of super-resolution reconstruction of single terahertz images..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220292 (2023)
Salient object detection method based on multi-scale feature-fusion guided by edge information
Xiangjun Wang, Mingyang Li, Lin Wang, Feng Liu, and Wei Wang
In this paper, an Edge-information Guided Multi-scale Feature-fusion Network (EGMFNet) is proposed to solve the problems of unclear boundary and incomplete structure of saliency map extracted by deep learning saliency target detection method based on FCN and U-shaped network architecture. EGMFNet uses Residual muti-ChaIn this paper, an Edge-information Guided Multi-scale Feature-fusion Network (EGMFNet) is proposed to solve the problems of unclear boundary and incomplete structure of saliency map extracted by deep learning saliency target detection method based on FCN and U-shaped network architecture. EGMFNet uses Residual muti-Channel Fusion Block (RCFBlock) and uses a nested U-shaped network architecture as the backbone model. At the same time, an Edge-information Guided Global Spatial Attention Module (EGSAM) is introduced at the lower level of the network to enhance spatial features and edge features. In addition, image boundary loss is introduced into the loss function, which is used to improve the quality of saliency map and keep clearer boundaries in the learning process. Experiments on four benchmark data sets show that the F values of the proposed method are increased by 1.5%, 2.7%, 1.8% and 1.6% compared with typical methods, which verifies the effectiveness of EGMFNet network model..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220344 (2023)
Infrared Technology and Application
Simulation research on IR radiation space distribution characteristic of fight plane
Zhongcheng Tong, Liang Wang, and Jun Wu
Considering the IR radiation space distribution research of fight plane is very little, in order to deeply understand IR radiation space distribution characteristics of fight plane in 3-5 μm, the infrared radiation ellipsoid model of tail flare is established, IR radiation characteristics of fight plane in different diConsidering the IR radiation space distribution research of fight plane is very little, in order to deeply understand IR radiation space distribution characteristics of fight plane in 3-5 μm, the infrared radiation ellipsoid model of tail flare is established, IR radiation characteristics of fight plane in different directions in 3-5 μm are simulated and calculated with the fight plane skin IR radiation model and the tail nozzle IR radiation model, and space distribution curves of IR radiation is given. The calculation shows that the infrared radiation of the aircraft is symmetrical with respect to the wing plane and the longitudinal symmetry plane of the fuselage. There are 4 extremes each in the tail and nose. The maximum value of infrared radiation is 5 177 W when the radiation direction is （ $ \pm $ ![]()
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Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220264 (2023)
Process development and characteristic evaluation of micro-bolometer device
Wei Liu, Bing He, Te Ma, and Gang Liu
Based on MEMS micro-bridge structure, micro-bolometer device was developed on standard semiconductor production line. Chemical Vapor Deposition (CVD) technology was used to deposit amorphous silicon (α-Si) film as sensing material. The within wafer thickness uniformity and the resistance uniformity of 1000 Å α-Si Based on MEMS micro-bridge structure, micro-bolometer device was developed on standard semiconductor production line. Chemical Vapor Deposition (CVD) technology was used to deposit amorphous silicon (α-Si) film as sensing material. The within wafer thickness uniformity and the resistance uniformity of 1000 Å α-Si film can be controlled to be less than 2%, and the Temperature Coefficient of Resistance (TCR) of 1000 Å α-Si film can reach at about -2.5%. Contact module of MEMS micro-bridge structure was developed by trench first approach, and electrical connection between MEMS and readout circuit was achieved by thin electrode layer on sidewall and bottom of the anchor and contact structure. Ti/TiN thin metal layer was used as electrode layer, and sensing resistor device was defined by the electrode layer patterns. Sensing material resistor device was fabricated by optimized integration scheme, which can achieve better process control on the sensing material loss and electrical layer sidewall recess etch amount. After device fabrication, room temperature resistance of device was about 250 kΩ with good ohmic contact. Device level TCR was measured at about -2%, and slightly lower than the data of thin film on blanket wafer. And the resistance data during the temperature raising up and down indicated that there was no hysteresis effect. Finally the MEMS device was released, and the optical and SEM data showed good physical performance, which can match the technical requirements of micro-bolometer production..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220279 (2023)
Influence of the discharge port structure on infrared characteristics of underwater vehicle thermal jet
Chengzhe Gao, Yongcheng Du, and Li Yang
The circulating cooling water of the underwater vehicle power system discharged from the discharge port, mixed with the environmental water for heat exchange and formed the thermal jet. The thermal jet diffused and floated in the environmental water and forms infrared characteristics on the surface of the water. In ordThe circulating cooling water of the underwater vehicle power system discharged from the discharge port, mixed with the environmental water for heat exchange and formed the thermal jet. The thermal jet diffused and floated in the environmental water and forms infrared characteristics on the surface of the water. In order to explore the influence of the structure of the discharge port on the infrared characteristics of the underwater vehicle thermal jet, this paper used the method of simulation analysis and experimental verification. Based on the CFD calculation software platform, the motion model of underwater vehicle was established, the structure of different radius-ratio oval discharge ports was designed, and the infrared characteristics of thermal jet were compared. The influence of the radius ratio of the oval discharge port on the infrared characteristics of the thermal jet was verified by the scale tank experiment, and the authenticity of the simulation calculation method and design parameters was verified at the same time. On the basis of oval discharge ports, the number and distribution position of discharge ports were further designed to suppress the infrared characteristics of thermal jet and improve the thermal stealth performance of underwater vehicles. According to the simulation calculation and experimental results, under the condition of the same discharge flow, the smaller the radius ratio was, the better the mixed heat transfer effect of the oval discharge port was, and the less obvious the infrared characteristics were. At the same time, increasing the number of discharge ports and adopting the symmetrical arrangement of discharge ports could further strengthen the temperature attenuation of thermal jet and reduce the surface maximum temperature..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220333 (2023)
Advance in high operating temperature HgCdTe infrared detector
Jun Chen, Zhongli Xi, Qiang Qin, Gongrong Deng, Yun Luo, and Peng Zhao
High operating temperature (HOT) infrared detector technology is an important branch of the third-generation infrared detector technology. The basic materials that can be used for high operating temperature infrared detectors are mainly Sb based and HgCdTe based. This paper introduces the lasest research progress of hiHigh operating temperature (HOT) infrared detector technology is an important branch of the third-generation infrared detector technology. The basic materials that can be used for high operating temperature infrared detectors are mainly Sb based and HgCdTe based. This paper introduces the lasest research progress of high operating temperature infrared focal plane module in Kunming Institute of Physics (KIP). The high operating temperature MCT based detectors developed based on p-on-n technology have reached good performance in the temperature range of 150 K with the NETD less than 20 mK. The weight of MCT 640×512 IDDCA module adapted with high efficiency moving magnet split linear cooler is less than 270 g with the detector length in optical axis direction less than 70 mm (F4). At ambient temperature, the steady power consumption of the module is less than 2.5 Wdc while the cool down time is less than 80 s, audible noise is less than 27 dB and self induced vibration force is less than 1.1 N. MCT HOT modules are now under environmental adaptability and reliability verification and commercial mass production of this detector will be realized after the verification test..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220462 (2023)
Invited Paper
Technical progress and system evaluation of all-time single photon lidar
Bo Liu, Yun Jiang, Rui Wang, Zhen Chen, Bin Zhao, Fengyun Huang, and Yuqiang Yang
Single photon lidar (also known as photon counting lidar) has detection sensitivity of single photon magnitude. Compared with traditional linear detection lidar, it can obtain longer detection distance, and it has become the frontier and development trend of lidar technology. However, the extremely high detection sensiSingle photon lidar (also known as photon counting lidar) has detection sensitivity of single photon magnitude. Compared with traditional linear detection lidar, it can obtain longer detection distance, and it has become the frontier and development trend of lidar technology. However, the extremely high detection sensitivity also makes the single photon lidar highly susceptible to the interference of background noise photons in detection, which greatly reduces its performance in daytime and greatly limits its application scope. Based on the detection principle of single photon lidar, this paper briefly reviews its technical development, analyzes the requirements of all-time work for single photon lidar detection system, and a new spectral filtering technique is adopted to greatly improve the detection performance of single photon lidar in daylight. At the same time, this paper also proposed a general evaluation model, which can be very intuitive to evaluate the detection performance of various lidar systems..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220748 (2023)
Lasers & Laser Optics
Optimal design for reducing diffraction loss of Littman-Metcalf grating external cavity semiconductor laser
Ping Zhou, Yongqian Wu, and Rongzhu Zhang
Based on the working principle of Littman-Metcalf type grating external cavity semiconductor laser, an external cavity structure which can reduce diffraction loss is designed. Based on the Littman-Metcalf structure, a reflector is added to feed back the zero-order diffraction light generated by the secondary diffractioBased on the working principle of Littman-Metcalf type grating external cavity semiconductor laser, an external cavity structure which can reduce diffraction loss is designed. Based on the Littman-Metcalf structure, a reflector is added to feed back the zero-order diffraction light generated by the secondary diffraction of the shining grating to the intrinsic cavity of the semiconductor laser. The expression of the external cavity loss of the new structure model is derived, and the external cavity loss, threshold current, output line width and output power of the two laser structures are simulated by the concept of equivalent cavity. The results show that the zero-order light fed back to the active region can effectively reduce the external cavity loss of the Littman-Metcalf structure laser and improve the coupling efficiency of the system, thus reducing the threshold current and improving the output power of the laser. At the same time, the output linewidth of the laser is further narrowed by improving the reflection efficiency of the external cavity. The factors affecting the output linewidth and output power of low loss Littman-Metcalf external cavity laser (end reflectivity, internal and external cavity length, blazed grating diffraction efficiency and mirror reflectivity) are also simulated and analyzed. It improves the theoretical guidance for the later laser production..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220206 (2023)
Simulation and experimental study on laser backscattering characteristics in turbid water
Xin Zhang, Siguang Zong, Bin Li, and Yang Yu
Due to the absorption and scattering of water, the beam energy will attenuate in the process of propagation, and the laser pulse will be widened, which restricts the detection range and accuracy of underwater lidar. Based on the application background of underwater weak and small target detection in turbid water enviroDue to the absorption and scattering of water, the beam energy will attenuate in the process of propagation, and the laser pulse will be widened, which restricts the detection range and accuracy of underwater lidar. Based on the application background of underwater weak and small target detection in turbid water environment, this paper establishes the Monte Carlo simulation model of underwater photon propagation, simulates the backscattering echo signal of water body with different attenuation coefficients and scattering rates, and analyzes the variation trend of the corresponding backscattering echo signal of water body. The simulation results show that the number of photons received by the laser echo signal of near-field water body gradually increases with the increase of attenuation coefficient of water body; With the increase of water scattering rate, the photon extinction speed of echo signal gradually decreases. The lidar echo signal test experiments under different turbidity are carried out. The experimental results show that with the increase of water attenuation coefficient, the laser backscattering echo amplitude of water gradually increases and the pulse width gradually widens. When detecting dim and small underwater targets in turbid water, with the increase of attenuation coefficient of water, the difference between water echo and target echo should be enhanced by gradually reducing laser energy or receiving system gain, so as to improve the signal-to-noise ratio of dim and small underwater targets in turbid water. The experimental results verify the theory and simulation results, and provide theoretical support for the laser energy selection and the gain design of the receiving system of the underwater weak and small target laser detection system under different water qualities in the turbid water environment..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220280 (2023)
Detection method of sidelobe peaks parameter for far-field measurement based on the diffraction inversion of sidelobe beam
Zhengzhou Wang, Yaxuan Duan, Li Wang, Gang Li, and Jiafu Guo
In order to solve the problem that high power laser far-field measurement can not effectively identify the parameters of each sidelobe peak in any direction of sidelobe beam, a detection method of sidelobe peak parameters of far-field measurement based on sidelobe beam diffraction inversion is proposed in this paper. TIn order to solve the problem that high power laser far-field measurement can not effectively identify the parameters of each sidelobe peak in any direction of sidelobe beam, a detection method of sidelobe peak parameters of far-field measurement based on sidelobe beam diffraction inversion is proposed in this paper. The main idea is to quantify the sidelobe beam image according to a specific angle sampling interval, and convert the two-dimensional sidelobe beam image into a set of one-dimensional sidelobe beam curves in all directions by angle transformation, then detect the parameters of each sidelobe peak of one-dimensional sidelobe beam curve at each angle, so as to obtain the parameters of each sidelobe peak in any direction of sidelobe beam. The main optimization measures are as follows: (1) Convert the two-dimensional sidelobe beam image into a set of one-dimensional sidelobe beam curves in all directions by angle transformation; (2) Detect the parameters of each sidelobe peak of one-dimensional sidelobe beam curve at each angle, count each sidelobe peak in all directions, and generate the maximum rings of each sidelobe peak; (3) Count the gray mean values of the maximum rings of each sidelobe peak, compare the gray mean values of the maximum rings of each sidelobe peak with the background noise, and select the minimum peak mean value greater than 1.5 times the background noise as the minimum measurable sidelobe peak signal of the whole sidelobe beam. The experimental results show that this method can effectively detect the parameters of each sidelobe peak in any direction of the sidelobe beam. The error between the mean value of gray maximum value and the theoretical value of gray maximum value in any direction is 0.477, and the error between the mean value of the maximum ring radius and the radius of the theoretical value of 5 sidelobe peaks is less than 1 pixel. This method improves the experimental accuracy and reliability of far-field measurement of high power laser based on the diffraction inversion of sidelobe beam, and it will lay a foundation for the accurate measurement of the far field of the high power laser in the large scientific facility in the future..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220281 (2023)
Status and development trend of overseas new type electric drive high-energy laser technology
Huihua Wang, Longxin Lin, Xin Ye, and Xiaoying Lv
The status and development trend of overseas new type electric drive high-energy lasers, such as PWG laser, thin-disk laser, liquid immersed solid-state laser, alkali vapor laser and coherent beam combining of fiber lasers, are discussed in this paper. The applied potential of these new type lasers used as light sourceThe status and development trend of overseas new type electric drive high-energy lasers, such as PWG laser, thin-disk laser, liquid immersed solid-state laser, alkali vapor laser and coherent beam combining of fiber lasers, are discussed in this paper. The applied potential of these new type lasers used as light source of laser weapon is analyzed. They can at least solve some problems faced by high-energy bulk solid-laser or fiber laser. Because of some shortcomings or problems to be solved, its output power, beam quality, or volume and weight cannot reach the level of a typical high-energy solid-state laser or fiber laser. The advantages and disadvantages of these new electrically driven high energy lasers are discussed in detail, and their technical development prospects are preliminarily analyzed and judged..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220283 (2023)
Wide-range multi-gas detection method based on wavelength modulation spectroscopy and direct absorption spectroscopy
Xiaohu Zhao, Pengshuai Sun, Zhirong Zhang, Qianjin Wang, Tao Pang, Miao Sun, and Feiyu Zhuang
When tunable diode laser absorption spectroscopy (TDLAS) is applied to the field of coal mine and petrochemical industry for gas concentration detection, it often needs to meet the requirements of high precision and wide dynamic range. Therefore, we use the time-division multiplexing method to combine the advantages ofWhen tunable diode laser absorption spectroscopy (TDLAS) is applied to the field of coal mine and petrochemical industry for gas concentration detection, it often needs to meet the requirements of high precision and wide dynamic range. Therefore, we use the time-division multiplexing method to combine the advantages of direct absorption spectroscopy (DAS) and wavelength modulation spectroscopy (WMS) technology to complete a high-precision wide-range calibration-free multi-gas detection system. The driving signal of the laser is designed as a periodic signal, which has linear scanning output signal superimposed with different high-frequency sin-wave modulation. It is used to complete the simultaneous calculation of low and high concentration inversion algorithms by time division multiplexing technology. Moreover, by optimizing the absorbance inflection point of the detected gas, the high-precision and wide-range detection of the gas concentration is realized. Under room temperature and pressure, the concentrations of CH4, CO and C2H2 are detected by experiments, and the absorbance at the optimal inflection point of the two algorithms is determined to be about 0.026 cm-1. The detection range of the system for the concentration of CH4, CO and C2H2 are 0-100%, 0-5000×10-6 and 0-1000×10-6, respectively. And also, the minimum concentration detection limits are 2.27×10-4, 0.21×10-6, and 1.68×10-6. The above analysis also shows that the system meets the requirements of wide dynamic range and the accuracy is better than the current coal mine industry standard in the whole range. Moreover, this method can meet the needs of various industrial field applications, and is conducive to promoting the application of laser absorption spectroscopy in industrial processes, security and other fields..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220284 (2023)
Detection of internal cavities in concrete with laser-acoustic method
Jinyang Zou, Yating Zhang, Xin Ding, and Jianquan Yao
The technology of detection of internal cavities in concrete with laser-acoustic method is one kind of remote sensing detection technology for internal cavity of concrete, which has the characteristics of fast detection and non-contact, meeting the needs of identifying the internal cavity of concrete in some cases wherThe technology of detection of internal cavities in concrete with laser-acoustic method is one kind of remote sensing detection technology for internal cavity of concrete, which has the characteristics of fast detection and non-contact, meeting the needs of identifying the internal cavity of concrete in some cases where it was not convenient to conduct contact detection. In this paper, focusing on the part of acoustic excitation, a laser acoustic concrete internal cavity detection system was built using accelerometers instead of laser vibrometers, and concrete specimens with internal prefabricated cavities were inspected. It was found that the presence of internal concrete voids would change the flexural rigidity of the structure above the voids, and when there was external excitation, the structure above the voids would show the phenomenon of bending vibration, the frequency of which was close to the first-order intrinsic frequency of the vibrating structure. The bending vibration in the defect area can be easily excited by using a high-power density pulsed laser, and when the cavity defect was shallow, the presence or absence of cavity inside can be judged by the characteristic response of the bending vibration in the frequency domain. As the depth of the cavity increased, the flexural rigidity of the structure above the cavity gradually increased, the amplitude of the bending vibration decreased, and the identification of the internal cavity will be difficult to be achieved by the characteristic frequency alone. In this case, the acceleration energy spectrum of the surface vibration signal can be used to characterize the vibration energy and determine whether there were cavities inside the concrete by the level of vibration energy. Based on the above theory, the cavity with a depth of 150 mm inside the concrete was successfully detected, which verified the feasibility of using laser acoustic technology to detect the cavity inside the concrete..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220306 (2023)
Effect of scanning speed on microstructure and properties of 300M steel cladding C276 coating
Guangfeng Yang, Feng Gao, Jing Cui, and Anyuan Xue
In order to improve the corrosion resistance of the surface of 300M ultra-high strength steel, four sets of coating samples with scanning speeds of 5 mm/s, 8 mm/s, 11 mm/s and 14 mm/s were prepared on the surface of 300M steel by laser cladding technology. The specimen was characterized by optical microscope, scanning In order to improve the corrosion resistance of the surface of 300M ultra-high strength steel, four sets of coating samples with scanning speeds of 5 mm/s, 8 mm/s, 11 mm/s and 14 mm/s were prepared on the surface of 300M steel by laser cladding technology. The specimen was characterized by optical microscope, scanning electron microscope, X-ray diffractometer, EDS energy dispersive spectrometer, microhardness tester, friction and wear machine and electrochemical workstation instrument, respectively, to characterize the macroscopic morphology, microstructure, phase composition, element distribution, hardness properties, friction and wear properties and corrosion resistance of the coating. The results show that after 300M steel is cladded with C276, the corrosion resistance and hardness of the coating are enhanced, but the wear resistance is worse than that of the original substrate, and the coating morphology is affected by the scanning speed. The greater the scanning speed, the flatness tends to be flatter, and the metallic luster is gradually deepened. At the same time, the phase types of the coating did not change significantly under different parameters, and the main phase was Ni-Cr-Co-Mo. Under the parameter of the scanning speed of 8 mm/s, the coating layer having the highest hardness is about 36.2% higher than that of the matrix, and it also has better corrosion resistance and other mechanical properties..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220328 (2023)
Thermo-mechanical coupling test method based on uniform double-sided laser irradiation
Jiawei Wang, Bin Li, Jianmin Zhang, Guobin Feng, Weiping Liu, Chenghua Wei, Yongchao Han, and Na Wang
In order to study the feasibility of testing the high temperature mechanical properties of materials with laser as heat source, a theoretical model and a numerical model were established to analyze the surface and internal temperature rise of materials heated by double-sided uniform laser spot. The results show that thIn order to study the feasibility of testing the high temperature mechanical properties of materials with laser as heat source, a theoretical model and a numerical model were established to analyze the surface and internal temperature rise of materials heated by double-sided uniform laser spot. The results show that the uniform temperature field can be formed in the heating area of the specimen by using the double sided uniform laser irradiation under the ideal condition. In order to verify the above conclusions, a thermo-mechanical test platform of laser irradiation with spot uniformity of 92% is established, and the high temperature tensile strength of CFRP laminates which are difficult to be heated quickly using traditional method is obtained based on the relevant test methods. The results show that the temperature uniformity of the specimen in the test area of laser heating center (10 mm×10 mm) is good. The specimen can be rapidly heated to 923 ℃ under uniform double-sided laser irradiation, and the maximum temperature fluctuation in the test area is 6.8%. The thermo-mechanical test method based on uniform laser double-sided irradiation has many advantages such as good generality, high temperature rise rate, high test temperature and high test efficiency. It provides a key technical support for further development of a universal test system of material/structure with high temperature rise rate and high temperature mechanical properties..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220329 (2023)
Phase noise of pumping in single-frequency fiber amplifier
Liangyou Duan, Zhen Liu, Qihao Shen, Xingkai He, Dingfu Zhou, and Yongke Zhang
The phase noise in the 100 Hz-1 kHz band of erbium-ytterbium co-doped single-frequency fiber amplifier was studied, and it was proved by experiments that the peak noise was the phase noise produced by the pump power supply. Based on the power transfer equations of erbium-ytterbium co-doped fiber amplifier and the heat The phase noise in the 100 Hz-1 kHz band of erbium-ytterbium co-doped single-frequency fiber amplifier was studied, and it was proved by experiments that the peak noise was the phase noise produced by the pump power supply. Based on the power transfer equations of erbium-ytterbium co-doped fiber amplifier and the heat transfer function of pump laser, the effects of pump power, pump wavelength and gain fiber length on the phase noise in 100 Hz-1 kHz band were analyzed numerically. The phase noise of the output laser was measured by using two-stage optical amplifier structure, and the experimental results were compared with the numerical simulation results, which proved the reliability of the theoretical model. This study optimized the phase noise characteristics of erbium-ytterbium co-doped single-frequency fiber amplifier with main resonance power amplifier structure and provided guidance for improving beam combining efficiency in coherent combination. In general, the aforementioned findings hold true for fiber amplifiers with main oscillation power amplification structure..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220332 (2023)
Materials & Thin Films
Characterization of single crystal Bi:YIG for microwave and optical communication
Lu Zhang, Jianbo Yang, Ziyan Zhang, and Peng Cai
Single crystal Bi and Gd substituted YIG films were prepared by liquid phase epitaxy method, and their microwave and magneto-optical properties were studied. The results show that the crystal quality of the sample is good, and the average surface roughness is 0.4 nm. The special saturation magnetization is 25 emu/g, anSingle crystal Bi and Gd substituted YIG films were prepared by liquid phase epitaxy method, and their microwave and magneto-optical properties were studied. The results show that the crystal quality of the sample is good, and the average surface roughness is 0.4 nm. The special saturation magnetization is 25 emu/g, and the saturation external magnetic field is about 650 Oe. In the range of 0-20 GHz, the Ferromagnetic Resonance Linewidth ΔH is less than 8 Oe, and the frequency is linear with the linewidth ΔH. At the wavelength of 1550 nm, the specific Faraday rotation angle of saturation state is about 0.1 (°)/μm, and the Faraday rotation of ±45° can be achieved with the superposition of two pieces of films. At 1550 nm, the transmittance is close to 90% and the absorption coefficient is lower than 16 cm-1. It has important application value in infrared magneto-optic and microwave communication..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20210869 (2023)
Optical Communication and Sensing
Investigation of the effect of narrow linewidth lasers on performance of coherent communication systems under atmosphere channels
Wanwang Fu, You Guo, Yuexing Zhang, Jisun Chen, Yijun Jiang, and Mi Li
In space downlink coherent laser communication systems, the laser linewidth will affect the performance of the communication systems. The narrow linewidth laser can effectively reduce the laser phase noise caused by the laser linewidth and is the prime preference for present-day coherent laser communication systems. WhIn space downlink coherent laser communication systems, the laser linewidth will affect the performance of the communication systems. The narrow linewidth laser can effectively reduce the laser phase noise caused by the laser linewidth and is the prime preference for present-day coherent laser communication systems. When optical signals are propagated in atmosphere channels, atmosphere turbulence will cause optical signals strength and phase fluctuations, which further affects the communication performance of the system. In response to the above problems, this manuscript derives the BER model for space downlink Quadri Phase Shift Keying (QPSK) communication system based on the principle of the QPSK communication system and further considered the linewidth of narrow linewidth laser, the fluctuation of optical signal intensity and phase fluctuations caused by atmosphere turbulence. Based on this model, the effect of narrow linewidth laser on the performance of space downlink coherent laser communication system under different atmosphere turbulence and communication rates is analyzed by numerical simulation. The results show that atmosphere turbulence not only severely affects the system performance but also weakens the effect of laser linewidth on the system performance. And the phase fluctuations caused by atmospheric turbulence have a greater effect on system performance than the light intensity fluctuations they cause. In addition, as the communication rate increases, the performance of the system decreases, and the laser linewidth has a reduced effect on the system performance. This paper has the practical reference for the optimal design and adjustment of space downlink coherent laser communication systems..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220219 (2023)
Research progress of chaotic free-space optical communication
Chao Wang, Yize Dong, Huiting Wang, Ji Gao, Zhixin Tian, Jianwei Gao, and Ning Jiang
With the rapid development of space communication technology, there is an urgent demand for information security. Free-space optical communication based on semiconductor laser, known for its terminal miniaturization, low power consumption, wide-spectrum and no electromagnetic spectrum constraints, has been widely used With the rapid development of space communication technology, there is an urgent demand for information security. Free-space optical communication based on semiconductor laser, known for its terminal miniaturization, low power consumption, wide-spectrum and no electromagnetic spectrum constraints, has been widely used in high-speed space communication. As chaotic free-space optical communication technology can encrypt optical signal in physical layer, it becomes a research hotpot of space optical communication. Combined with the current development process of free-space optical communication, chaotic laser communication and chaotic free-space optical communication, this paper introduces the key technologies of chaotic free-space optical communication, and focuses on the research progress of laser beam ’s pointing, acquisition and tracking technologies, turbulence mitigation technologies of chaotic free-space optical communication and chaotic free-space optical synchronization technology. Besides, the future research directions and several key technologies that can be used for reference of chaotic free-space optical communication are also prospected, aiming to provide reference for the further development of chaotic free-space optical communication technology..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220296 (2023)
Application of optical communication technology of large-scale UAV based on aviation backbone network
Fengfeng Xue, Shanghong Zhao, Yongjun Li, Qin Tian, and Haotong Fu
At present, radio frequency technology is used between platforms in the aviation backbone network, which has shortcomings such as low transmission rate, limited frequency band resources, and susceptibility to electromagnetic interference. It is difficult to meet the requirements for safe and high-speed transmission of At present, radio frequency technology is used between platforms in the aviation backbone network, which has shortcomings such as low transmission rate, limited frequency band resources, and susceptibility to electromagnetic interference. It is difficult to meet the requirements for safe and high-speed transmission of aviation data in military and civil fields such as aviation safety and combat command. While optical communication has significant advantages in high-speed and reliable transmission of aviation information, with the advantages of ultra-high speed, ultra-large bandwidth, strong anti-interference ability, and good confidentiality. In order to improve the capability of wireless communication between flight platforms of aviation backbone network, on the basis of analyzing and summarizing of the research status and experiments of key technologies of airborne optical communication at home and abroad, at first this thesis makes an assumption and description for the application scenario of domestic large UAV as backbone network mobile relay in the current aviation field, then analyzes deeply the airborne optical communication requirements of large UAV. At last systematically summarizes the key technologies and future development trend of laser communication of large aviation UAV, which provides a certain theoretical reference and basis for the application and development of airborne optical communication technology in large aviation UAV..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220331 (2023)
Optical Design
Stray light analysis of off-axis four mirrors system based on two-dimensional function PST
Kaiyu Yang, Ning Jin, Dan Yang, Long Pu, Man Xu, Shulin Dong, and Lei Su
Off-axis four mirrors systems are opto-mechanical core components of multiband common aperture airborne observation and aiming systems to adapt to their future development. This type of systems is easily affected by strong stray light outside the field of view. The point source transmittance (PST) of stray light in thoOff-axis four mirrors systems are opto-mechanical core components of multiband common aperture airborne observation and aiming systems to adapt to their future development. This type of systems is easily affected by strong stray light outside the field of view. The point source transmittance (PST) of stray light in those systems is generally required to be no more than 10-4 order of magnitude. Accordingly, omnidirectional scanning calculation of PST is the key to analyze and suppress stray light of them. For the asymmetry of the optical system, PST as a two-dimensional function varying with the horizontal and vertical angle of stray light was set up to evaluate the influence of external stray light. Besides, the conversion relationship between the horizontal and vertical angle and the process quantity of rotation about coordinate axis required for opto-mechanical modeling was established. The simulation control program was compiled, which realized the automatic tracking of stray light and the two-dimensional scanning calculation of PST by calling LightTools software. For a multiband common aperture off-axis four mirrors system, the PST distribution of stray light in all directions within the whole incident hemispherical space was calculated, so as to screen out 3 series of stray light that had a great impact on the application of airborne observation and then find their transmission paths and key surfaces. Based on this, the inner baffles and vanes were designed to optimize the stray light trap structure in the system, so that the peak value of PST of the system was reduced from the original 10-1 level to 10-4 level, especially less than 10-7 outside the avoidance angle range, which could meet the application requirements of airborne photoelectric observation and aiming systems. It provides a basis for the analysis and suppression of stray light of off-axis four mirrors systems..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220330 (2023)
Structure design and verification of primary mirror assembly for large off-axis TMA camera
Jian Yuan, and Lei Zhang
Large aperture rectangular mirror is one of the core components in large off-axis TMA camera, focusing on the primary mirror with clear aperture of 1250 mm×460 mm in Jilin-1KF01C satellite, the structural design method for 1.2 m scale mirror assembly with large aspect ratio was systematically discussed, and the deLarge aperture rectangular mirror is one of the core components in large off-axis TMA camera, focusing on the primary mirror with clear aperture of 1250 mm×460 mm in Jilin-1KF01C satellite, the structural design method for 1.2 m scale mirror assembly with large aspect ratio was systematically discussed, and the developed mirror was verified in detail. Based on material properties and existing processes, the mirror body was made of reaction bonded silicon carbide, semi-closed lightweight form was adopted, the optimal combination of structural parameters was determined through two-objective global optimization. The final design weight of mirror body was 41.8 kg, with the facepanel 5 mm thick and the thinnest stiffener 3 mm thick. The classical back three-point support scheme was adopted, the structural parameters of the biaxial flexure hinge in the flexible support were optimized, so as to take into account fundamental frequency and thermal stability of the component, and match the centroid position of the mirror body. The assembling process for the primary mirror assembly and the corresponding stress relief measures were put forward. Test results showed that the full aperture surface accuracy of primary mirror under testing gravitational condition was 0.016λ (λ=632.8 nm) in root mean square value, and the full aperture was 0.019λ after turning 180°. The tested 1st fundamental frequency of the assembly was 128.5 Hz, and the root mean square value of primary mirror basically remained stable after large scale random vibrations and wide range temperature cycles. The primary mirror assembly not only has good dynamic and static characteristics, but also has the features of high surface accuracy and good stability, which can meet the application requirements of high-performance space optical system..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220363 (2023)
Buchdahl model of achromatic method for unfocused systems
Jicheng Zhang, Yuegang Fu, Yuan Hu, and Weiqi Liu
The dispersion vector analysis method based on Buchdahl model can be used to guide material selection and replacement in optical design to obtain material combinations with good achromatic effect, but at present the theory is only applied to the design of focused systems due to the limitation of mathematical form, and The dispersion vector analysis method based on Buchdahl model can be used to guide material selection and replacement in optical design to obtain material combinations with good achromatic effect, but at present the theory is only applied to the design of focused systems due to the limitation of mathematical form, and there is no precedent for guiding the design of unfocused systems. To further investigate the application of this theory to the unfocused system, a deformed expression of the dispersion vector scale factor applicable to the unfocused system is proposed, and the material selection of a seven-fold telescopic unfocused system is carried out by this method. The optimized system has a maximum chromatic aberration of only 2.705×10-5D (Diopter) at 0.707 aperture. The focal shift difference between 632.8 nm and 1 064 nm wavelengths is 0.000 21 D, and the maximum focal shift in the wavelength range is only 0.004 7 D. The chromatic aberration of the system is effectively corrected, and the MTF of each field of view completely reaches the diffraction limit. The research results enable the dispersion vector analysis method based on Buchdahl model to be applied to the design of unfocused systems as well, providing a new idea for the selection of achromatic material combinations for unfocused systems..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220374 (2023)
Optical Imaging
Light field camera modeling and distortion correction improvement method
Shourui Yang, Wanying Duan, Wenyu Ai, and Shengyong Chen
As a new type of imaging system, the light field camera can directly obtain 3D information from a single exposure of the image. In order to make more sufficient and effective use of the angle and position information contained in the light field data, complete more accurate scene depth calculation, and thus improve theAs a new type of imaging system, the light field camera can directly obtain 3D information from a single exposure of the image. In order to make more sufficient and effective use of the angle and position information contained in the light field data, complete more accurate scene depth calculation, and thus improve the accuracy of the 3D reconstruction of the light field camera, it is necessary to establish accurate geometric modeling and precisely calibrate its model parameters. This method starts from the thin lens model and pinhole imaging model, the main lens is modeled as the thin lens model, the micro modeling for pinhole imaging model, combined with the two-parallel-plane model of the light field camera, each extracted feature point is associated with its ray in three-dimensional space, the physical meaning of each parameter in the internal reference matrix is explained in detail, as well as the process of determining the initial value in the process of calibration. Furthermore, based on the radial lens distortion model, the tangential lens distortion model and the nonlinear optimization method based on ray reprojection error are further applied to improve the calibration method of light field camera. The experimental results show that the RMS ray reprojection error of this method is 0.332 mm. Compared with the classical Dansereau calibration method, the ray reprojection error accuracy of the proposed method is improved by 8% after nonlinear optimization. The derivation process of scene points and specific pixels analyzed in detail in this method has important research significance for the calibration of optical field cameras, which lays the foundation for establishment of optical model and the initial calibration of light field cameras..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220326 (2023)
Image sharpness evaluation and variable-step fusion focusing method
Hongliang Pan, Jinxia Sun, and Xizhen Han
The imaging of the cross wire target on the CCD is generally affected by the ambient light and the optical path. The cross wire image generated by the focal length of different positions will be blurred and out of focus, and the extraction of the center point of the cross wire target will be seriously affected. The traThe imaging of the cross wire target on the CCD is generally affected by the ambient light and the optical path. The cross wire image generated by the focal length of different positions will be blurred and out of focus, and the extraction of the center point of the cross wire target will be seriously affected. The traditional Sobel algorithm ignores the edge information and is easily affected by noise. Therefore, a two-stage fast search auto focusing method with variable-step size is proposed, which improves the image sharpness evaluation function of Sobel operator and combines the coarse and fine focusing. The method first evaluates the image sharpness by using the spatial domain of the image, and then selects the two-stage focusing mode according to the optical design. The first step is coarse adjustment. When the focus position is quickly found, fine adjustment is performed until the focus position is found. Experimental results show that compared with other algorithms, the auto focusing failure rate is 2%, the focusing time is 1242 ms, and the focusing stroke is -25-30 mm. The combination of the image sharpness evaluation function and the two-stage focusing mode through this algorithm has high accuracy and good real-time performance..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220342 (2023)
Thermal design of Hα solar space telescope
Hongyu Guan, Lei Wang, Kuncheng Feng, Yanjun Xu, Fan Jiang, and Chengshan Han
Hα solar space telescope has the functions of solar spectral imaging and full-disk solar imaging, which is multi-functional and highly integrated. It is located inside the satellite payload cabin, its on-orbit attitude is changeable, and it has the working mode of continuous observation, which leads to the harsh thermaHα solar space telescope has the functions of solar spectral imaging and full-disk solar imaging, which is multi-functional and highly integrated. It is located inside the satellite payload cabin, its on-orbit attitude is changeable, and it has the working mode of continuous observation, which leads to the harsh thermal environment of focal plane assembly and electric boxes, and puts forward higher requirements for thermal design. Through the integrated design of the payload with satellite and the reasonable layout of the telescope's structure, the radiation heat dissipation channel was reserved in the satellite payload cabin near the camera. The heat dissipation surface was reasonably designed to export the working heat consumption quickly, ensuring that the temperature of each component met the index. By building the thermal equilibrium test platform, the thermal analysis, thermal equilibrium test and in-orbit data was compared under high and low temperature conditions. The maximum temperature difference of each electric box under the same working condition was ≤4 ℃, the correctness of the thermal design was verified, which ensured the normal operation of Hα solar space telescope in complex space environment. It has certain reference significance for the thermal control design of such space solar telescope..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20221395 (2023)
Photoelectric Measurement
Terahertz vector measurement system based on AlGaN/GaN HEMT terahertz mixer
Yiting Liu, Qingfeng Ding, Wei Feng, Yifan Zhu, Hua Qin, Jiandong Sun, and Kai Cheng
Vector measurement is an important technology for beam testing of antennas and quasi-optical systems in terahertz band. This paper introduces a terahertz vector measurement system based on a high-sensitivity AlGaN/GaN high-electron-mobility transistor (HEMT) terahertz detector integrated with a quasi-optical lens and wVector measurement is an important technology for beam testing of antennas and quasi-optical systems in terahertz band. This paper introduces a terahertz vector measurement system based on a high-sensitivity AlGaN/GaN high-electron-mobility transistor (HEMT) terahertz detector integrated with a quasi-optical lens and waveguide together, which reached the noise equivalent power of -113 dBm/Hz in heterodyne mode at 340 GHz. A hardware circuit is established based on the double frequency-down-conversion technique to suppress phase noise in the system. The experimental results indicate that the minimum measurable power is 119 nW and the phase stability is better than 4° of the system. Measurement of the distribution of both terahertz amplitude and phase has been achieved based on this coherent AlGaN/GaN HEMT detector. An arrayed terahertz vector measurement system could be developed based on this work..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220278 (2023)
Diffuse reflection characteristics measurement of new type spaceborne solar calibration diffuser in ultraviolet band
Jiexiong Zeng, Yu Huang, Zhanfeng Li, Guanyu Lin, and Yuan Li
The Lambertian diffuse reflectance characteristics of the spaceborne solar calibration diffuser and its radiation attenuation characteristics directly determine the long-term accuracy and stability of the on-orbit radiation calibration of space remote sensing instruments. In order to effectively improve the on-orbit raThe Lambertian diffuse reflectance characteristics of the spaceborne solar calibration diffuser and its radiation attenuation characteristics directly determine the long-term accuracy and stability of the on-orbit radiation calibration of space remote sensing instruments. In order to effectively improve the on-orbit radiation calibration accuracy of spaceborne ultraviolet hyperspectral detection instruments, based on the introduction of commonly used solar calibration diffuse reflector materials in the field of space remote sensing, a new type of ultraviolet wavelength diffuser material is proposed: high purity opaque fused silica material HOD, and the diffuse reflection Lambertian characteristics and radiation attenuation characteristics of the new high purity opaque Fused silica HOD diffuser and the traditional aluminum diffuser are compared by testing. The results show that after 32 equivalent solar hours (32ESH) of vacuum ultraviolet irradiation, the attenuation of the high purity opaque Fused silica HOD diffuser at the wavelength of 290 nm is 7.5%, which is better than 10% of the traditional aluminum diffuser. And the Lambertian maximum cosine deviation of the traditional aluminum diffuser around 290 nm is about 40%, while the high purity opaque Fused silica HOD diffuser is about 10%. Therefore, the diffuse reflection characteristics of the new high purity opaque Fused silica HOD diffuse reflector in the ultraviolet band are better than those of the traditional aluminum diffuser. The high purity opaque Fused silica hod diffuser has better diffuse reflection Lambertian characteristics and stronger vacuum ultraviolet radiation attenuation characteristics, so it can improve the long-term accuracy of the on-orbit radiometric calibration of space ultraviolet remote sensing instruments..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220339 (2023)
Two-position initial alignment method for redundant rotating inertial navigation system
Tao Zou, Lifen Wang, Yuan Ren, and Ting Zhu
Redundant Rotating Inertial Navigation System (RRINS) can further improve the reliability of the system on the basis of traditional rotating inertial navigation system. Aiming at the high-precision initial alignment requirements of this type of system, A two-position initial alignment method was studied by taking the rRedundant Rotating Inertial Navigation System (RRINS) can further improve the reliability of the system on the basis of traditional rotating inertial navigation system. Aiming at the high-precision initial alignment requirements of this type of system, A two-position initial alignment method was studied by taking the regular tetrahedral redundant rotating inertial navigation system as an example. Firstly, every three gyroscopes and three accelerometers constituted a combination. The zero bias correlation and redundancy configuration of the inertial device under each combination were established. And the RRINS two-position stop scheme was designed to estimate the zero bias of the corresponding inertial device. But in some special cases, the observation position needs to be increased. Then, the results obtained by each inertial device under different combinations were averaged, and the average value was used to compensate the measurement information of the corresponding inertial device. Finally, based on the compensated inertial device output performs the initial alignment of the RRINS. Mathematical simulation and experimental verification results show that the method can effectively estimate the zero bias of the inertial device under different two-position schemes. In the simulation, the bias estimation error of the gyroscope is within 4%, and the bias estimation error of the accelerometer is basically within 2%. Compared with the case without bias compensation, the initial alignment accuracy is improved by more than 10 times. In the experiment, the initial alignment accuracy in both horizontal and azimuth directions was improved, and the heading angle alignment error was reduced by about 100 times. At the same time, the method can also be extended to redundant rotating inertial navigation systems with other configuration schemes, which has certain reference significance for improving the initial alignment accuracy of such inertial navigation systems..
Infrared and Laser Engineering
- Publication Date: Jan. 25, 2023
- Vol. 52, Issue 1, 20220414 (2023)
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