This PDF file contains the front matter associated with SPIE Proceedings Volume 11885, including the Title Page, Copyright Information, and Table of Contents.

As a common uniform shaping device, microlens array is widely used in laser lighting system. ZEMAX software is used to simulate the light path of microlens array unit size, microlens array thickness, microlens array unit curvature radius, adjacent microlens array spacing distance, integral lens focal length change, and to compare and analyze the illumination spot when the above factors change. The results show that: the smaller the size of microlens array unit, the larger the size of illumination spot; the smaller the curvature radius of microlens array unit, the larger the size of illumination spot; the smaller the distance between microlens arrays, the larger the size of illumination spot; the larger the focal length of integral lens, the larger the size of illumination spot. The conclusion provides a basis for the selection of microlens array in lighting system.

In this paper, the differences of microstructure and mechanical properties of 2205 duplex stainless steel between preheating laser-induction hybrid welding (LIHW) and post-heating LIHW were compared by the optical microscope, nanoindentation, Vickers hardness and tensile machines. The results of the nano-indentation experiment show that the elastic modulus and hardness of ferrite are 42% and 64% larger than that of austenite, respectively. With the increase of LIHW heating power, the austenite proportion increases distinctly. Furthermore, the increase of the austenite results in the decrease of hardness and ultimate tensile stress. By quantifying the microstructure and mechanical properties, pre-heating LIHW exhibits greater superiority than post-heating LIHW with a heating power of 49.1 kW, laser power of 3 kW and welding speed of 30 mm/s.

Due to the limitation of satellite payload performance and the influence of space environment, large-capacity information transmission between satellites has always been a key difficulty in the field of inter-satellite information transmission. Laser communication has the characteristics of fast transmission rate and large information capacity, which is very suitable for large-capacity inter-satellite information transmission. This article introduces the related concepts of laser communication, investigates the development status of space laser communication and laser communication relay system, briefly introduces the representative laser communication satellite system, and summarizes the advantages and disadvantages of laser communication. The inter-satellite laser communication relay system is designed based on two different application scenarios. The inter-satellite distance and information transmission window are simulated based on the SGP4 model to verify the feasibility of the relay system to extend the inter-satellite laser communication. The engineering realization of the follow-up system has a certain meaning.

In order to extend the service life of injection mold, the use of laser rust removal was used to repair the surface quality of mold steel in this paper. The surface corrosion of mold steel was removed by using the laser dry cleaning method, then the surface roughness was restored to the initial state to meet the performance requirements of manufacturing. By analyzing the experimental results, the influence of laser energy density, spot overlap rate and scanning times on improving the surface quality of corroded area was obtained. It was shown that when the laser energy density, spot overlap rate and scanning times is 26 J/cm², 18% and 3 times respectively, the optimum surface roughness of Sa2.32μm can be obtained, which meets the production requirements. Compared with traditional rust removal methods, the laser rust removal of the mold surfaces deserves more extensive research and application due to its advantages of high efficiency, precision and environmentally friendly.

Recently, the application of femtosecond laser ablation of nickel to prepare super-hydrophobic structures in marine anticorrosion has become more and more mature, but the processing efficiency is slow, which limits its large-scale application. In this study, a method for improving the efficiency of ablating nickel through multiple scanning of femtosecond lasers single pulse is proposed. The experimental results show that when the total processing time is the same, the higher scanning speed and more scanning times will promote the increase of the groove depth formed by the ablated nickel compared with the low scanning speed. This phenomenon has been verified under three different laser fluences. Compared with 25 um/s, the ablation efficiency is increased by 42.6%, 48.2% and 55.4% when scanning speed is 200 um/s, respectively. The difference in ablation efficiency in the experiment is related to the fact that femtosecond laser ablation of nickel will change the physical and chemical properties of the bottom of the material.

It is a known fact that 2A14 aluminum alloy is susceptible to cracking in the weld metal when welded with fusion processes. Hot cracking sensitivity of 2A14 aluminum alloy in fiber laser welding is first evaluated experimentally. The cracking behaviors of the specimens are evaluated by fishbone cracking test. The fracture morphologies of the weld are observed by optical microscope (OM) and scanning electron microscope (SEM). The results show that the crack formed in fiber laser welding with filler wire of 2A14 aluminum alloy is solidification crack. There is an obvious laser power threshold to form thermal cracks in different welding speeds. Hot cracking tendency is obvious when the laser power is below the threshold. There is no hot cracking when the laser power is greater than or equal to the threshold. The hot cracking rate of the welding speed 3.0m/min is slightly higher than the welding speed 4.5m/min.

The most practical laser coding styles is analyzed, including pulse interval codes, pseudo-random codes input by logic feedback functions and pseudo-random codes with random pulses inserted. According to the principle of code generation, the corresponding laser pulse code control software is designed. The results show that the laser code waveform generated by the software of the host computer is stable with strong applicability. The software lays the foundation for the realization of laser pulse code hardware.

As a non-contact measurement method, laser vibration measurement technology has shown great application value in many fields, especially in the field of aerospace. Laser vibration measurement technology is widely used in aerospace engine blade modal and vibration test, solar panel modal test, aerospace device welding process characteristics test and aerospace component damping test. With the help of advanced laser vibration measurement technology, many vibration measurement problems in aerospace field can be solved. This paper introduces the principle and key technology of laser Doppler interferometry vibration measurement technology, which shows that the technology has the advantages of high measurement accuracy. The application status of laser vibration measurement technology in aerospace field is introduced, and the future development trend of laser vibration measurement technology is prospected.

Recently with the massive explosion of remote sensing observation satellites and the deployment of low earth orbit (LEO) broadband communication satellites, the demand for data transmission of data relay satellites has increased sharply. Higher and higher capabilities have been proposed for data relay satellites. However, the current situation is the limited on-board storage capacity, the low microwave link rate. In view of the huge amount of data produced by various medium and low orbit vehicles, a satellite-to-ground laser communication application system is constructed based on the analysis of domestic and foreign relay satellite systems. The overall business process is also researched of this laser communication application system, from customer satellite resource application, link control to data return. Then the subsequent work is prospected.

Sapphire is a widely used material, but is difficult to process by using mechanical or chemical methods. We used a femtosecond laser to fabricate highly curved periodic micro/nano grating structures on a sapphire surface. The effects of laser repetition rate, laser scanning speed, laser polarization direction and scanning direction, and laser fluence on the resulting curved grating were studied. Finite difference time domain (FDTD) simulation software was used to investigate the formation of the curved grating and explain the reason for the formation of the structure being dependent on the distance between two adjacent pulses, which is determined by the scanning speed. This method can be used to process complex patterns with structural colors on a sapphire surface, and different colors could be observed from different angles under white light.

In recent years, optical chaos as a new research hotspot has attracted extensive attention. In order to improve the performance of chaos-based applications, we need to study the numerical value of its output chaotic signal.. In this contribution, the effects of injection parameters, i.e. the frequency detuning and injection strength, on time-delay signature (TDS) concealment and bandwidth enhancement of the three cascade-coupled semiconductor ring lasers (SRLs) are numerically investigated. The results show that, under the proper conditions, both the TDS elimination and bandwidth enhancement can be reached in the third SRL of cascade-coupled system.

Laser-induced forward transfer of liquid film is widely used, and the viscosity of liquid directly affects the jet formation and deposition results. In this paper, the femtosecond (fs) laser-induced forward transfer of medium viscosity (0.3 Paꞏs) liquid film was observed by time-resolved shadowgraph imaging, and it is found that the jet changed from a stable state to an explosive state with the increase of laser fluence. However, the deposition results show that when the driving laser fluence increased, the deposition droplet height first increased, then decreased, and then increased. Combined with the observation results, it is proved that the change of jet state is the reason for the above-mentioned trend of the deposition height. These results provide a reference for the observation and deposition results of femtosecond laser-induced medium viscosity liquid films transfer.

In recent years, artificial satellites have developed towards miniaturization and micro-nano. The propulsion system is indispensable for micro-nano satellites. The key component of the electrospray thruster is the emitter made of porous material, which generates micro thrust by emitting ionic liquid. The hardness and brittleness of porous ceramics are relatively large. Traditional machining methods and long-pulse laser fabricating have disadvantages such as low machining accuracy, poor surface quality, severe tool wear, and large heat-affected zones. This paper studied the femtosecond laser fabrication of porous borosilicate ceramics to obtain strip-shaped and cone-shaped convex structure which could be used for electrospray thruster emitter. The rough machining and finish machining of porous ceramics were studied and the laser fabricating parameters were optimized. Combining the advantages of rough machining and finish machining, the "twostep machining" was used to fabricate porous ceramics, which improved the machining efficiency while ensuring the machining accuracy and machining quality.

As a very promising method for improving the performance of organic photovoltaic (OPV) devices, femtosecond laser processing is advantaged at high processing precision, small heat-affected zone and can achieve selective morphology control of the active layer. However, almost current studies focused on single pulse processing. In this work, the single and double pulse processing laws of poly(3-hexyl-thiophene) (P3HT): phenyl-C61-butyricacid methyl ester (PCBM) blend films were explored by using temporally-shaped femtosecond laser processing system. When single pulse processing is used, it indicated a structural transformation process from bump to ablation crater. The temporally-shaped double pulse femtosecond laser processing results showed the effect of ablation enhancement compared with the single pulse, and the ablation depth and the ablation area increased. (For bumps, it facilitated further fragmentation). When the double pulse delay is 0.5ps, the effect of ablation enhancement (bump fragmentation) was the strongest. This letter proposed an ablation enhancement approach based on temporally-shaped femtosecond laser processing, which can further control the morphology of the active layer for promoted performance of OPV devices.

Graphene has emerged excellent electronic, optical and mechanical properties as a layered semiconductor, and opening its bandgap through modulation further expands its practical applications. Direct laser writing has been widely used in material modulation, owing to its high precision, convenient local processing capacity. As an important factor, laser parameters play a crucial role in the ablation of materials. In this paper, the influence of laser parameters on the ablation was investigated by adjusting the energy and numbers of laser pulse. The saturation of ablation was found in the case of 500 pulses, and the ablation threshold of graphene paper was calculated to be 0.2 J/cm2. The results above have a positive effect on the modulation and the further devices fabrication of graphene paper.

Processing the Si₃N₄ ceramic is a big challenge because of its high hardness and brittleness. Femtosecond (fs) laser is an excellent method to process the Si₃N₄ ceramic. However, the temporal evolution of the fs laser induced plasma from the initialization to the disappearance is still lacking for deeply understanding the laser-matter mechanisms. In this study, we employ the pump-probe shadowgraphy and the ultrafast plasma imaging to observe the whole shockwave evolution on Si₃N₄ ceramic. We find that the shockwave propagates in a spherical law and the velocity of shockwave decreases rapidly in the first 50 ns, and finally approaches to the speed of sound at the delay of 430 ns. The relationship between plasma melting, expansion and shockwave propagation was revealed to provide further insight into the fs laser ablation of Si₃N₄ ceramic.

As a typical tumor suppressor and transcription factor in cancer biology, p53 protein is involved in DNA repair, the cell cycle regulation and programmed cell death. The p53 protein in human blood can be linked with tissue alterations for more than 50% human cancer, and its concentration can be used for early-stage cancer diagnostics and related risk assessments. In this work, we demonstrated a high resolution biomedical sensor. It is based on a micro Bragg fiber grating (mFBG) as a sensing probe to form lasing in a fiber laser ring resonant cavity. It is able to detect the p53 protein by measuring the fiber laser wavelength via the optical wavelength meter (OWM). Compared with the traditional sensing system based on the full-spectrum measurement, a higher signal-to-noise ratio and more stable output can be obtained, which improves the wavelength resolution and measurement speed. The optical fiber biomedical sensor successfully maintains its specificity for p53 protein, and has a promising application in clinical oncology diagnosis.

The use of quantum key distribution for encryption to realize the secure transmission of information is a research hotspot in the field of secure communication. In theory, it has a high degree of security with quantum mechanics as a guarantee. In particular, continuous variable quantum key distribution has the advantages of simple quantum state preparation, relatively high key rate and low detector cost, so it has attracted wide attention from all over the world. However, the continuous variable quantum key distribution will be affected by factors such as fiber type and fiber attenuation when it is transmitted in the fiber channel. Therefore, a large number of experimental tests must be carried out in the fiber channel before the quantum key distribution device is connected to the optical network. Therefore, this paper conducted continuous quantum key distribution experiments in different lengths of terrestrial optical fiber G.652D and submarine optical fiber G.654D. Among them, the quantum key generation rate reaches an average of 10kbit/s, and the quantum error rate is within 10%. As the distance increases, the variance of the transmission coefficient and the shot noise becomes smaller and the amplitude of the excess noise fluctuation becomes larger. The negotiation efficiency is above 92.44%. The experimental results show that continuous quantum key distribution has good compatibility in both G.652D and G.654D fibers. The experimental data provides a large amount of data support for subsequent research on the access of quantum key distribution equipment to optical networks.

Global environment and climate change are the focus and frontier subjects of ecology, biogeochemistry and environmental science. Simultaneous in-situ monitoring of multiple atmospheric pollution components base on laser absorption spectroscopy technology has become an effective way for in-depth analysis and accurate identification of atmospheric pollution sources by analyzing the correlation of their concentration data. In view of the wide variety of actual atmospheric pollutants, the source, transformation mechanism, and transportation process of each component are extremely complex and overlap phenomenon, the in-depth analysis of atmospheric pollution sources is an important challenge. The depth analysis of air pollution sources is the key basis for scientific control of the air pollution. It is of great significance to carry out in situ monitoring techniques and analytical algorithms for various pollutants. In this paper, carbon monoxide (CO), a typical pollutant in the atmosphere, is firstly selected and analyzed by using HYSPLIT backward trajectory model, and the reliability of the proposed algorithm is verified. In addition, with PM2.5 as the analysis target, the backward trajectory of air mass during 72 h of pollution was simulated by HYSPLIT model for Beijing's heavy pollution during January 26-28, 2020. The potential transport channels and pollution contribution sources of PM2.5 in different areas to Beijing were analyzed by daily trajectory clustering analysis.

In this paper, radiation spectrum design methods of material were proposed. Effect of temperature and atmospheric transmission on the infrared radiation transmission of materials was studied. The radiation properties of different materials were analyzed at different temperature. The transmission of aircraft surface materials infrared radiation was studied, according to the environment and the radiation transmission. Moreover, the spectrum of the two materials with the consistent emissivity was studied. Material has less radiation characteristic peak within the 3.0−4.3 μm and low radiation intensity within the 8−14 μm, which has good spectral stealth properties at 250−450 K. The radiation spectrum peak of the material was not obvious within the 4.3−8.0 μm owing to the low transmittance of atmosphere. In conclusion, research results have good significance for the spectral stealth design of materials, and can potentially be used in infrared spectral stealth technology and equipment.

Aiming at the requirement of real-time matching between the large field of view image of the night vision goggles on helmet and the small field of view image of the infrared rifle sight in the individual observation and sighting system, this paper uses the Zynq heterogeneous embedded platform and adopts the software and hardware co-design method to build a system that can match the two images in real time. Experiments show that when the large field of view image is 640×480 pixels, the small field of view image is 200×200 pixels, and the frame rate of the two cameras is 25 frames per second, this system’s matching frame rate reaches 23 frames per second, which meets the needs of real-time matching. The system has a certain degree of robustness to rotation and zooming, and its matching accuracy is high.

Single-photon imaging technique is a new type of light detection and ranging (LIDAR) technology used for weak signal detection which has a high sensitivity up to single-photon energy level. It has a broad prospect of application in the field of underwater imaging. Range-gated technique has been proved to be effective in reducing the backscattering noise and improving the signal-to-noise ratio (SNR) during the data acquisition stage. The range-gated synchronous control system is a key component of the underwater single-photon imaging system. At present, most range-gated synchronous control systems have the defects of low stepping regulation precision and narrow dynamic regulating range. This paper designs a novel range-gated synchronous control system which has both a wide dynamic regulating range and a high stepping regulation precision of gating distance. It is composed of a coarse regulation part and a fine regulation part which are both based on the field programmable gate array (FPGA). The simulation results show that the dynamic range of the system’s gated distance can meet the requirement of imaging as far as 7km, and the stepping regulation precision can reach as high as 39ps, with the gate width adjustable. The system designed in this paper guarantees a high SNR data acquisition and has a strong adaptability under various distance scenarios along with extra advantages of lower cost, smaller volume and lighter weight. These features will make a great improvement in the crypticity and portability of the whole underwater singlephoton imaging system.

We study, through simulation, the intensity properties of the ideal Bessel-Gaussian(BG) and combined Bessel(CB) vortex beams through atmospheric turbulence. The results show that there are many petals outside the intensity hole of a CB vortex beam. When the topological charges are the same, the intensity-hole radius and aperture averaged scintillation of a CB beams are much bigger, but the energy efficiency is much smaller than that of a BG beam. With the increasing of the topological charges, the intensity-hole radii and aperture averaged scintillation of two types of Bessel beams increase, but the energy efficiency decrease.

We proposed a simple and flexible method for fabricating computer-generated holograms (CGHs) on crystalline silicon via femtosecond laser-assisted with chemical etching. Femtosecond laser irradiation led to the transformation of crystalline silicon into amorphous silicon, and its chemical activity is significantly reduced, so it can be used as an etching mask in alkaline solution. The amorphous silicon mask led to the formation of nanopillar structure after wet etching. The height of the nanopillars could be flexibly adjusted by controlling the etching time. By means of laser dynamic scanning, we realized the fabrication of holographic array on silicon. The diffraction pattern of the CGHs on silicon becomes clearer with the increase of the height of the nanopillar.

The design of university library should conform to the principle of "suitable, economical, green and beautiful", among which, the "green" should highlight the use function of the building. We advocate green energy saving and conform to the current energy situation. In view of the low utilization rate of natural light in the reading room of university libraries and the relatively common problem of artificial lighting, this article focuses on analyzing many influencing factors of natural lighting in the reading room of university libraries. There are plane function division, storey height, depth, opening room, single and double side lighting and related shading measures.

VO₂ film is expected to be used in smart radiation devices (SRD) due to changes in infrared reflection caused by semiconductor-to-metal transition (SMT). In this work, a tunable thermal emitter which consisted of Al layer, CaF₂ layer and VO₂ layer was designed to achieve variable emittance with temperature. The variation of dielectric parameters of VO₂ shell caused by temperature change was used to regulate the absorption characteristics of the structure, to realize the positive emittance-switching performance of the thermal emitter device. It was found that the total emittance of the device could reversibly change from 0.03 at 30℃ to 0.72 at 90℃ with an emittance variability of 0.69 in 4-14 µm. In addition, the influence of the thickness of CaF₂, VO₂ layers and the intermediate layer material on the emittance variation of the device was studied. These results shown that the device has the best VO₂ and CaF₂ layer thicknesses of 20nm and 1000nm, respectively. Particularly, too high refractive index of the intermediate layer material will cause the device to produce multiple resonance peaks at high temperature, which will reduce the average emissivity of the entire band, resulting in a smaller change in the emissivity of the thermal emitter.

Laser ranging technology is a widely used non-contact active measurement method, which could quickly and accurately obtain distance data. The research propose of this paper is to use python to process the data of Yanqing wall-mounted highway which scanned by laser ranging technology, and visualizing point cloud data. The results demonstrated that the system can quickly and accurately describe the shape of the tunnel in a non-contact manner, thereby reducing the limitations of traditional geological survey methods, which could satisfy the data source and the basis for judging the shape of the tunnel. Further works such as filtering and surface reconstruction could be finished according to the needs of the project ,which meet more project needs.

Due to the lack of visual information in conventional fire detection methods, false alarms and missing alarms are easy to occur. N-heptane and aviation kerosene were used as experimental fuels to carry out oil pool fire combustion experiment. Combining the convolutional neural network and the principle of image correlation to analyze the classification and recognition of combustion images and the frequency of flame oscillation, which were used as parameters to determine whether a fire occurred. The results show that the peak flame temperature and increasing rate of temperature of combustion is slightly lower by low pressure, which cause jitter of temperature and the trend is more obvious. The O2 decreases firstly and then increases and finally tends to be stable, while, the content of CO2 increases firstly and then decreases and finally comes to be stable at 96kPa. However, Under the equidistant combustion time series of n-heptane and aviation kerosene, the average flame oscillation frequency is 3.26 Hz and 3.06 Hz, respectively, and the error between its theoretical flame oscillation frequency is small, and the accuracy rate is as high as 90%. It can be seen that low pressure has a greater influence on the fire behavior of combustion, which could provide theoretical support for studying the key technologies of fire alarm under low pressure.

With the development of high-performance IRFPA, temperature field image measurement has been applied to the fields of industry and agriculture, national defence, health and epidemic prevention. In order to obtain a clearer and more accurate image of temperature field, we developed a coaxial beam splitting medium wave/long wave dual-band infrared temperature field image reconstruction experimental system using uncooled wide-band IRFPA. Then, a low frequency noise correction method in gradient domain is used to reduce the temperature measurement error caused by the non-uniformity of detectors. The temperature measurement error of central field of view is less than 3.5% and that of quadrangular field of view is less than 4.5% in the temperature range of 20~80°C by calibrating the temperature of the system using blackbody. Experimental results show that the method is effective. Finally, the equivalent temperature field image to the typical outfield image is given.

We develop a 3x3 -channel Bionic Compound Eyes Imaging System (BCEIS, which is composed of an optical system and a mechanical system) and apply it to target positioning. First, we analyze the overlapping condition based on the imaging model of the BCEIS. Then, considering the relation between the pixel coordinates of image points and world coordinate of the target is nonlinear, we fabricate three well-designed general regression neural networks (GRNNs) to position the target under three conditions where the FOV of four channels, six channels and nine channels overlaps at the same time respectively (the image point of each channel is obtained under three conditions). In order to overcome limitations of the GRNN, we sample a group of image points which cover the FOV of the system under above three conditions to train the network, and then utilize the testing set to verify the reliability of the three GRNNs. The experimental result shows that the positioning accuracy is the highest in the area where the FOV of nine channels overlaps simultaneously, which is followed by the accuracy in the area where the FOV of six channels overlaps at the same time. The positioning accuracy is the lowest in the area where the FOV of four channels overlaps simultaneously. Furthermore, we find that GRNN performs better both in positioning accuracy and time consumption when compared with BP network. Adopting the GRNN to position the target provides a new way in applications such as object tracking, robot navigation and etc.

Eu doped CaAlSiN3 phosphor was successfully prepared by high-temperature solid phase method using Ca₂Si₅N₈:Eu as major raw materials. The phase transition and luminescence properties were studied in detail. It is found that the phase changes from Ca₂Si₅N₈ to CaSiN₂ when the temperature reaches 800 ℃. Then CaAlSiN₃:Eu phosphor was synthesized by the solid phase reaction: (Ca,Eu)SiN₂+AlN→(Ca,Eu)AlSiN₃ when the reaches 1500 ℃. The morphology and luminescence properties of CaAlSiN₃: Eu with different Eu concentration was also studied.

HF gas is an important decomposition product of SF6 gas in Gas insulated switchgear (GIS), and is an important index to evaluate the moisture environment and potential faults of high-voltage combination appliances. Therefore, HF gas detection is of great significance. A tunable diode laser absorption spectroscopy (TDLAS) sensor based on distributed feedback laser (DFB) is used to detect HF gas in GIS gas chamber.The transmitting and receiving circuits of laser signals are designed to realize the modulation of the transmitting laser signals and the control of the laser temperature. Meanwhile, dynamic amplification and voltage tracking are carried out on the detection output signal to further improve the stability and sensitivity of the system. The different sample number corresponding harmonic amplitude index fitting results show that the saturated adsorption after second harmonic amplitude basic remains the same, reaching constant extremum, firstorder index fitting correlation coefficient R₂ is 0.995, 0.996, 0.997, respectively, PVDF to sample three times after adsorption saturation, gas testing response time is 3 min, optimal performance. Analysis of adsorption mechanism in SUS304 adsorption process, electrostatic attraction plays a key role, while PVDF and PTFE materials have developed microporous structures, and Vander Waals force plays a major role. HF gas calibration experiment shows that the linear relationship between gas concentration and second harmonic amplitude is well, the fitting coefficient R₂ is 0.9985, the maximum absolute error of concentration inversion is -0.83, the maximum relative error is -2%, and the lower limit of detection is 0.85 PPM. To sum up, TDLAS sensor used for HF gas detection in GIS gas chamber was designed, and the advantages of PVDF material optical path cell in adsorption time and detection accuracy were verified by experiments, and the adsorption mechanism was analyzed from the perspective of material structure.

As micro-supercapacitors are more and more widely used in the field of energy storage, how to fabricate microsupercapacitors simply and quickly is very important. We demonstrated a one-step and effective method for the fabrication of flexible micro-supercapacitors. Irradiated by the double-pulse femtosecond laser, the polyimide was converted to a conductive holey carbon with uniform pore size distribution. At the same time, the scribing of the electrode is completed. Compared with the single-pulse femtosecond laser, the specific capacitance of holey carbon electrode prepared by doublepulse femtosecond laser was higher than that by single-pulse femtosecond laser. This one-step approach of the fabrication of holey carbon electrodes with excellent capacitive properties makes it possible to integrate micro-supercapacitors as miniaturized energy storage units with other micro/nano portable electronic devices in the future.

Two-dimensional MoS₂ materials with structures like graphene have become hot topics of research in recent years, due to their unique physical and chemical properties. The sol-gel method of preparation of materials is mild and simple. Especially, the uniformity of the reactants at the molecular level cannot be achieved within a short period of time by other methods. The MoS₂-SiO₂ composite materials were prepared by a sol-gel method. The results of confocal microscopy, Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy showed that the samples prepared in this study contained MoS₂ and the surface of the film was not cracked.

An electromagnetically actuated dual-axis MEMS scanning micromirror for lidar applications is introduced, besides a novel radial magnetic field actuation system is designed. The dual-axis scanning micromirror with large aperture which the plate size of 2.6 mm in diameter was realized utilizing patterned single-turn electroplated copper coils, which combined with a concentric permanent magnet assembly forming radial magnetic field. Based on the basic of this working principle, the displacement response outputs of different torsion beam structures were compared by theoretical analysis and finite element simulation. The serpentine elastic beam was chosen as the external torsion axis of the micromirror device because of its large displacement output. The coupling magnetic field of the permanent magnet assembly was analyzed and simulated to achieve the maximum magnetic field intensity at the coils. Horizontal resonance frequency of the presented micromirror was 3376.2 Hz and vertical resonance frequency was 419.46 Hz, in addition, maximum deflection angle of approximately ±25.2°in horizontal direction and about ±17.4°in vertical direction were achieved at resonance. The design of the micromirror meets the requirements of MEMS lidar for large mirror size and wide scanning field of view.

Radiometers are used in a various number of measurements applications. The output detector is the main element in the radiometer which determines its linearity and dynamic range. In this paper, the square-law detection principle of Schottky diode and multiplier is introduced. The multiplication detection module and the amplifer-filter circuits are designed. The multiplication detector takes the analog multiplier as the core, and the differential circuit is used at the signal input. The output linearity of 0.99999 is achieved in the bandwidth of 50 MHz ~ 2GHz and the dynamic range of -16dBm ~ 4dBm. Compared with the diode detector, the multiplication detector has the advantages of large effective bandwidth, wide dynamic range, high linearity and good stability.

Due to the influence of mechanical environment, large range temperature change and atmospheric pressure, the space multispectral camera has a certain amount of defocus in the optical imaging system. In order to improve the imaging quality of the multispectral camera, if the traditional CAM focusing mechanism is adopted, it is difficult to meet the requirements of high precision focusing for fast response due to its disadvantages such as large volume, poor efficiency and low precision. Therefore, a new focusing mechanism is designed in this paper, which is composed of rhomboid amplifier large piezoelectric ceramic actuator, flexible hinge support structure and high-precision capacitance sensor. The mechanism drives the flexible support guide structure of the parallelogram by means of a rhomboid amplifier large PZT actuator with three points distributed uniformly and symmetrically at 120°, so that the lens base can move in a straight line along the Z direction. The high precision capacitance sensor is used as the feedback element to ensure the focusing accuracy of the mechanism reaches nanometer level. The test results show that the focusing range of this mechanism is ±21.91um, the focusing speed is 438um/s, the focusing precision is 50nm and the tilt error is 1".

Asymmetric metal micro/nano-structures can generate multiple modes of plasmon resonance, and have been widely used in the fields of structural color anti-counterfeiting, multiple information coding, etc. In this paper, the slit-shaped femtosecond laser was proposed to fabricate anisotropic elliptical microbumps in a non-ablation state on gold films. The influence of pulse energy and slit width on the size and the ratio of long and short axis of elliptical microbumps were studied. And the reflectance spectra of the elliptical microbump arrays under different polarizations were measured, which verified the polarization-dependent spectral characteristics of the elliptical microbump structures.

The performance analysis of underwater optical wireless communication (UOWC) with digital pulse interval modulation in anisotropy oceanic turbulence environment is investigated. We aim at the packet error rate (PER) of UOWC system using Gaussian-Schell model beam and avalanche photodiode receiver. Based on the generalized Huygens-Fresnel principle, the received light intensity is derived. The effects of PER variations with anisotropy factor, modulation order of DPIM, coherent parameters of the GSM and the ratio of temperature to salinity contributions to the refractive index spectrum are investigated.

Haze can affect the optical properties of the atmosphere, so it is necessary to study the UV (ultraviolet) polarization characteristics of haze for atmospheric optical communication. The research focus of this paper is as follows: Based on the single-scattering polarization model of ultraviolet light, the Mie scattering theory and the T-matrix method are used for research. The polarization degree of ultraviolet scattering between spherical and ellipsoidal haze particles with different radii, different real and imaginary parts is simulated. The results show that the smaller the effective radius of the particle and the real part of the complex refractive index or the larger the imaginary part of the complex refractive index, the greater the maximum linear polarization degree. For ellipsoidal particles, the smaller the particle deformation, the greater the maximum linear polarization.

All-optical clock extraction plays an essential role in WDM-PON. An ONU clock extraction and wavelength conversion scheme based on FP filter and cross gain modulation (XGM) is proposed in WDM-PON. First, we introduce the theory of the all-optical clock extraction and wavelength conversion. The simulated investigations are conducted to verify the suitability and feasibility of the proposed method, which proves clock signal can be reused at ONU and backward Rayleigh scattering effect can be reduced.

One of the major bottlenecks in the commercialization of micro-light-emitting diodes (micro-LEDs) displays is the “massive transfer”. Monolithic integration of the driving element and the micro-LED pixel can radically avoid the technical problem of massive transfer. In this paper, the integrated device was fabricated on a gallium nitride (GaN) substrate. The device uses graphene as the channel material for the driving field-effect transistors (FETs) to control the micro-LEDs. However, in the traditional process, the residue of the ultraviolet photoresist on the surface of the graphene will cause severe doping, which resulting in the inferior performance of the fabricated graphene FETs (GFETs) device. To get higherperformance integrated devices, a new process method was intended in this paper. The performance of the GFETs was enhanced by optimizing the fabrication process, and the current control range of the GFETs for micro-LED was up to 11mA. The new process method adopts the PMMA thin film underlayer photolithography method, which effectively avoids the severe doping problem caused by ultraviolet photoresist residues on the graphene surface when fabricating GFETs for integrated devices. Based on the new fabricating technology, the transconductance and carrier mobility of GFETs had significantly enhanced. In conclusion, this research further expands the application of two-dimensional materials in the field of optoelectronic displays. Furthermore, the application of the new fabrication process of the integrated devices can be used as a technology accumulation to promote the commercialization of micro-LEDs.

Periodic silicon nanostructure arrays play crucial role in the fields of the optics, nanophotonics and biotechnology. It’s imperative to fabricate controllable silicon nanostructures with high precision and cost-efficiency. In this study，an elegant approach was proposed for fabricating morphology controllable periodic 3D silicon nanostructure arrays through chemical etching assisted femtosecond laser near-field modification. The employed transparent dielectric microsphere monolayer acted as micro-lens array to confine laser pulse energy in subwavelength region transforming crystalline silicon into amorphous silicon. Based on the etching rate difference between the two phase state in etchant, 3D silicon nanostructure arrays were fabricated. Nanostructures with elliptical and circular shape formed under linearly and circularly polarized laser irradiation and with subsequent wet chemical etching. Various surface nanostructure were prepared including disk-like, ring-like, cone-like and volcano-like nanostructures by tuning laser fluence and chemical etching duration.

In the fields of coloring, printing and dyeing, color is one of the most important indicators for product quality evaluating. It is helpful to monitor and control color quality in time if on-line measurement is used in production process. Textiles vibrate irregularly when moving along the production line and most materials have texture, which make it difficult to measure color accurately. To solve this problem, both illumination uniformity and sampling aperture size should be studied. In this paper we designed a novel on-line textile color measurement system. In the system, the lighting path was designed with a four-edge light pipe, which achieved the illumination uniformity of 90%. The suitable size of sampling aperture was found by comparing the influences caused by measuring distance changing and surface texture when using sampling apertures of different sizes. Finally, the system has been tested for repeatability of color measurement and the result was 0.02, which showed that the performance of the system has already met the requirement for on-line textile color measurement. Compared with similar foreign products of the same level, this system has simpler structure and lower price.

Transverse Mode Instability (TMI) effect has become the biggest obstacle limiting the further improvement of output power and beam quality in high-power fiber lasers. For 2μm-band high-power thulium-doped fiber laser, the simulation is carried out using semi-analytical theoretical model. The results show that the TMI threshold is negatively correlated with the core radius, signal wavelength and positively correlated with the pump wavelength. On the other hand, reducing the relative intensity noise can slightly but not obviously improve the TMI threshold. The relationship curve between them is nearly logarithmic. The simulation provides an effective reference for further improving the TMI threshold.

We proposed a doped silicon microhole arrays metasurface absorber that works in the long-wave infrared region. The absorbance of the absorber is significantly increased, we found the real part of the doped silicon refractive index decreases, which leads to the decrease of the equivalent refractive index of the structure. Guided mode resonance exists in the structure, which forms Fano resonance after interaction with external radiation. Fano resonance can limit the electromagnetic field in the structure, improve the interaction between light and doped silicon, and realize the purpose of absorption enhancement.Simulated results verify that the absorbance of the absorber with the optimized structure above 37.7% at 9.67 μm.

With the rapid development of modern agriculture, LEDs as artificial light sources are playing an increasingly important role in modern agriculture. However, the uneven lighting of LEDs will cause the uneven quality of agricultural products. For requirements of plant light source on highly uniform illumination distribution, we put up an improved Pigeon- Inspired Optimization algorithm to design uniform light of the LED array. Using this method, we designed four different shapes of LED arrays. Through optimizations on MATLAB and simulation analysis on optical software TracePro, we obtained the illumination uniformity of 91.03%, 91.64%, and 92.89% for hexagonal, circular, and rectangular LED arrays, respectively, and the illumination uniformity of freely arranged LED array is up to 93.64%. The results show that LED arrays with near-optimal illumination uniformity on the target plane were obtained by this method. In addition, based on these LED arrays obtained, we investigated the relationship between the uniformity of the target plane and the vertical distance of the LED array. It is concluded that as the vertical distance increases, the illumination uniformity of the target plane increases, but the average illumination value decreases. The improved algorithm proposed in this paper lay a solid foundation for the uniform lighting design of LEDs.

This article analyzes the basic definition and application characteristics of optical-mechanical-electrical integration technology. The author studied the specific applications of optical mechatronics technology in CNC production technology, sensor technology, industrial robots, building construction fields, intelligent production lines, automated production, flexible manufacturing systems, and computer integrated systems based on the design points of the optical mechatronics technology control system. The purpose of this article is to improve the level of cognition of optical mechatronics technology and promote the rapid economic development of related industries.