Fuzzy control is used in wavefront correction and its feasibility has been confirmed because it does not depend on the response model of deformable mirror. The wavefront correction effect of fuzzy proportion integration differentiation (PID) control in adaptive optical system is assessed, including testing fuzzy correction bandwidth, selecting fuzzy input and output domains, and optimizing fuzzy rule base and wavefront weighted template. Experimental results show that the selection of fuzzy domain is reasonable, and the better results are obtained with a 3×3 wavefront weighted template. When the initial values of KP、KI and KD of PID controller are 0, the rule base with membership degree positive distribution is more suitable for the fuzzy output domain. When the refresh rate of the Hartmann-Shack sensor is 120 Hz, the system correction bandwidth is 5-6 Hz, which is consistent with the conventional PID.

A new type of waveguide collimated projection system uses diffraction grating, which can complete the beam coupling, expansion and imaging by only using one waveguide plate. So it is more conducive to system integration and miniaturization, and it has great research value. A Matlab model of the diffraction grating in the new type of waveguide collimated projection system is established based on the rigorous coupled wave theory. According to the performance requirements of the system, the models of the coupled grating, extended grating and exit grating are analyzed, and the structure and related parameters of the diffraction grating are designed. The results show that the new blazed grating is used as the coupled grating, and the extended grating is designed as a combination of traditional binary grating and novel binary grating, while the output grating is a blazed grating. The waveguide collimated projection system is uniformly imaged, whose field of view is 24.8°×30°. The system can be used for the integrated and miniaturized displays with small occupation and light weight.

Reducing the strain sensitivity of fiber Bragg grating (FBG) strain sensor is one important method to solve issues of small measurement range and undetectable large strain. In order to monitor stress and strain changes of components during use, one composite technology of spiral and slant gratings is proposed. The theoretical relationship between the measured strain by FBG and the actual strain of specimen is established. The measurement experiment of the grating strain sensitivity under different spiral-slant angles is done. The experimental results show that the proposed method can effectively reduce the strain sensitivity of FBG and increase the strain measurement range of FBG.

A photonic bandgap type liquid crystal photonic crystal fiber with high thermal tuning sensitivity around room temperature is designed when we fill the cladding air holes of solid-core photonic crystal fiber with liquid crystal of 5CB type. The variation in photonic bandgap with fiber structure parameters, the thermal tuning characteristic of the position of photonic bandgap, the variation in fiber confinement loss with cladding hole ring number and the thermal tuning characteristic of confinement loss are investigated by the finite element method. The results show that the photonic bandgap position of photonic crystal fiber depends strongly on cladding hole diameter. The confinement loss decreases as the ring number of cladding hole increases. The photonic bandgap position and the confinement loss curve are red shifted, and the average thermal tuning sensitivity of 10.3 nm/℃ is achieved at the position of the minimum confinement loss when the temperature increases from 25.1 ℃ to 34.8 ℃. Around the central wavelength of photonic bandgap, a high coupling efficiency between the photonic bandgap type liquid crystal photonic crystal fiber and the fiber with the same structure unfilled with liquid crystal is obtained.

The noise types of photoconductive HgCdTe detector which is used to detect long-wave infrared are analyzed, and corresponding noise models are established. Combined with light intensity distribution models under different atmospheric turbulence conditions, the bit error rate expression of long-wave infrared wireless laser communication system is obtained when we use the digital pulse interval modulation mode. On the basis of selecting typical simulation data, the numerical simulation analysis for the bit error rate of long-wave infrared wireless laser communication is carried out with different atmosphere turbulence intensities, communication distances, transmission rates and average transmission powers. The results show that the long-wave infrared has the strong ability to resist the atmospheric turbulence, and the bit error rate can be satisfied when we choose proper transmission power and transmission rate.

A new method for regulating the time-domain characteristics of pulse fiber amplifier is proposed. According to the basic principle of pulse time-domain waveform distortion in fiber amplifier and the specific requirement in practical application of output pulse, the optimum input pulse required to generate target output pulse is obtained by the stochastic parallel gradient descent (SPGD) algorithm. Several particular output pulses can be generated in numerical simulation, which proves the effectiveness of the proposed method. The input pulse can be changed continually when we use the SPGD algorithm, so that the practical output of fiber amplifier comes close to the target output. The control strategy is easy and the output pulse converges rapidly. Good results can be achieved with the proposed method when we generate the pulses with linear boundaries such as rectangular, M-shaped and triangle pulses, or generate the pulses with curved boundaries such as parabola and ellipse pulses, and the proposed method can be widely applied to generating variety types of target pulses.

A reference-based pre-equalization (RPE) technology is introduced. The technology, which is based on the self-coherent mixing frequency technology, can measure the accurate qualitative information of transfer function in self-coherent homodyne detection system and pre-emphasize the transmission signal. The RPE technology can pre-compensate all electrical and optical linear loss, including the bandwidth limitation of modulator and power amplifier and the high-frequency component loss caused by optical pre-filter. The calibration performance of RPE strongly depends on the laser linewidth of both the transmitter and the receiver. We investigate the RPE calibration performances of several laser sources which are universal in self-coherent homodyne detection system, and develop a phase correction algorithm to obtain accurate qualitative information of the transfer function. The feasibility of the algorithm is verified when we use several types of laser sources in coherent optical communication system with polarization-multiplexed quadrature phase shift keying. The wavelength division multiplexing bandwidth limitation is 25 GHz and the rate is 32 Gbit/s.

The influences of semiconductor optical amplifier parameters on all-optical wavelength conversion system with high speed polarization multiplexing-orthogonal frequency division multiplexing (PM-OFDM) are analyzed and simulated. The SOA parameters, such as gain saturation, optical confinement factor and carrier concentration in active region, are related to the wavelength conversion efficiency. Before achieving SOA gain saturation or nearby SOA gain saturation, the injection current, the carrier concentration, and the optical confinement factor effect on the SOA gain coefficient changing, and ultimately effect the wavelength conversion efficiency. The PM-OFDM signal with the rate of 40 Gbit/s is achieved directly without crosstalk after all-optical wavelength conversion when we improve the SOA parameters.

When a water jet freely falls onto a rigid plane with a low flow rate, light rings around the water jet can be observed if the point that the water jet contacts with the plane is illuminated by a laser beam. It is proved experimentally that stable ripple structures surrounding the contact point are essential to form the light rings of water jet. The equation of corrugated stability can be established based on the Bernoulli′s equation and the dispersion relationship of disturbance wave propagation derived by the Plateau-Rayleigh instability theory, and then experiments are designed to investigate the properties of the light rings of water jet. The theoretical and experimental results show that the spacing, brightness and quantity of the light rings are straightly related to the falling height and the initial flow velocity of the water jet, the variety of the rigid plane and the depression angle. The spacing between the light rings becomes smaller with the increasing falling height and initial flow velocity of the water jet. The less the energy loss of laser in a rigid plane is, the brighter the light rings are. There is a proper depression angle range to observe the light rings. It is concluded that the bigger the depression angle is, the more the observed light rings are. Consequently it is better to overlook the light rings for a satisfied observation effect.

Point cloud registration is an important issue in 3D information processing. The traditional point cloud registration needs a huge amount of computation, thus it is not suitable for real-time and mobile computation. In order to solve the problem of traditional point cloud registration method, a method based on convolutional neural network is proposed. The depth image of point cloud is calculated and the differential feature vector of depth images extracted by the convolutional neural network is regarded as input of fully connected neural network to calculate registration parameters. Iteratively executing the above process until registration error is acceptable. Experimental results show that the point cloud registration based on convolutional neural network is simpler in computation, more efficient in registration rate, and less sensitive to noise and outlier than the traditional methods.

Fourier ptychographic microscopy (FPM) is a recently developed computational microscopy. Different from the conventional microscopy, the FPM generally employs a programmable LED array as an illumination source for angular illuminations. The intensity of LED illumination is corresponding to the emitting angle. The luminous intensity decreases rapidly with the increasing of emitting angle. The illumination intensity of different angles cannot be consistent, which leads to the decline of the reconstructed image quality. Consequently, the intensity correction of low-resolution raw images is consequently needed before the iterative phase retrieval process. The reasons of the different angles of illumination intensity inhomogeneity are introduced. Numerical simulations demonstrate the necessity of the intensity correction. Finally, the experimental results of physical intensity correction are given.

Based on the linear mixing principle of sesame oil and adulterated oil, a photometric method for direct determination of the doping ratio is proposed by using the absorbance of sesame oil, adulterated oil and their mixed oil. The error analysis method is used to analyze the formula of doping ratio. It can be seen that the optimal detection wavelength region is the region where the absorbance difference between sesame oil and adulterated oil is the biggest. The spectrophotometer functions of the SpectraMax Plus 384 microplate reader and the assembled visible-near infrared spectral acquisition system are used to test the sesame oil doped with peanut oil and soybean oil. For the sesame oil with the doping volume ratio of peanut oil and soybean oil larger than 10%, the testing results of the spectrophotometer show that the correlation coefficients between the calculated values and the actual values of the doping ratio are 0.9992 and 0.9997, and the standard errors are 0.0084 and 0.0054, respectively. Meanwhile, the testing results of the visible-near infrared spectral acquisition system show that the correlation coefficients are 0.9997 and 0.9994, and the standard errors are 0.0047 and 0.0069, respectively. The experimental results indicate that the proposed linear photometric method for quantitative determination of doping components in sesame oil is feasible and accurate.

In order to enhance the scanning frequency and delay time of the fast optical delay line (FODL) device based on the principle of involutes, an optical delay line device with high speed and high stability is proposed. The angle deflection and optical path difference change of emergent light caused by the assembly error of the delay line device is analyzed. The characteristics of the device including the scanning frequency, delay time, delay stability and delay linearity are tested with the Michelson interference system. The experimental results show that the delay line device possesses high assembly accuracy and can realize high-speed and high-stability scanning and large optical delay, with the scanning frequency of 100 Hz, the delay time of 167.45 ps, the delay distance of 50.06 mm, the stability error of 0.25%, and the linearity error of 0.05%.

Based on the rotation of laser displacement sensor, and taking the rotating axis as measuring basis, one novel method for measuring the deep hole straightness is presented and also verified. The experimental results show that, with the precision of laser displacement sensor of ±2 μm, the on-line measurement of the hole straightness can be done with the proposed method. Compared with the relative true value offered by three-coordinate measuring machine, the error is less by 12%. The model just needs the spindle and the feed component of machine tool and can be implemented easily.

In order to obtain a narrow linewidth laser with good short-term frequency stability, a free running laser is locked in a Fabry-Pérot (F-P) reference cavity which has the characteristics of vibration isolation, constant temperature and high fineness. To reduce the influence of temperature on laser frequency stability, the F-P cavity is generally made of glass material with ultralow-expansion (ULE) coefficient. There is a special temperature point called inflection point temperature for ULE glass, and the ULE coefficient of glass is almost zero under such special temperature. For the inflection point temperature is always higher or lower than the room temperature, we design an active temperature control equipment which can control the F-P cavity temperature in the range of -5-40 ℃ in high vacuum environment, with a temperature fluctuation less than ±0.005 ℃ in one day. The temperature control equipment is employed to ULE F-P cavity system with the working wavelength of 729 nm, and the average linear frequency drift is within 100 mHz/s when the reference cavity temperature is controlled near the inflection point temperature of 17.3 ℃.

The dimple and bump microstructures on 304L stainless steel surface are processed by modulating the power and pulse duration of a long pulsed laser, and their morphology features are observed. The research results show that dimples with good morphology can be obtained under short pulse duration and high power and the dimple depth and diameter increase first and then decrease with the increase of laser power when the pulse duration is fixed. In contrast, bumps with good morphology can be obtained under long pulse duration and low power, the influence of power on bumps is stronger than that of pulse duration, and when the power reaches a certain value, the bump height and diameter approach to saturation.

The texturing process on 45 steel disc surface is done by using Nd∶YAG solid pulsed lasers and the textured arrays with different micro-hole depths are formed. The Ni-MoS2 composite coatings are prepared on the surfaces of textured steel discs. The test of the tribological performance of Al2O3 ceramic ball/45 steel disc is done, and the worn morphology of sample surfaces is analyzed. The results show that number of pulses has a small influence on the maximum diameters of micro-holes. As the number of pulses increases, the depths of micro-holes and the volumes of internal cavities increase significantly. Under the dry friction condition, the friction coefficient of textured-coating is less than that of untextured-coating by 0.1-0.15, and the friction coefficient is further decreased with micro-hole depths increasing. The textured coating with 40 pulses has the best antifriction property, and its wear life is three times of that of the textured coating with 20 pulses.

The process of laser welding with filler wire (LWFW) is presented to solve the problem of negative reinforcement of thin sheet weld seam, and to satisfy the requirement of high precision assembly in laser self-fusing welding. LWFW experiment about Hastelloy C-276 shielding materials is carried out, and the effects of process parameters on the weld forming are studied. The microstructures, element distribution and micro-hardness of weld joints in different zones are analyzed. The results indicate that the weld joints with controllable positive reinforcements on both top and bottom surfaces by using LWFW can be obtained, and the weld appearance with uniform reinforcements and contact angles on upper and lower surface is available under the optimized process parameters conditions. Obvious grain refinement in weld joint and no obvious heat-affected zone at the junction of base metal and fusion line are observed. The element distribution of weld is uniform in different melting zones, and macro segregation is not found, but micro segregation of Mo in columnar dendrite zone is significant. The micro-hardness of weld joint is well-distributed in different regions and the value is basically equivalent to that of base metal.

The influence of the key process parameters of CH4/H2/Cl2 inductively coupled plasma (ICP) on the etching performance was systematically investigated. The flow density and the ratio in CH4/H2/Cl2 gas mixtures are optimized. Therefore, an effective method can be used for fabricating Bragg grating with high etching rate, low damage ICP etching and high quality surface on special designed InP/InGaAlAs multiple quantum well wafer. Combined with post-process, four wavelengths 1.3 μm distributed feedback laser array was fabricated based on multi-period λ/4 shifted Bragg grating. The typical threshold current and the external differential efficiency are about 11 mA and 0.40 W/A, respectively. And the side mode suppression ratio of each laser diode is more than 46 dB. It can be verified that ICP etching processing in Bragg grating has high quality and reliability.

With the factorial design experiment, the influences of laser process parameters on hole taper and heat affected zone (HAZ) of fluorophlogopite glass ceramic are studied. Regression equations between taper, HAZ thickness and laser process parameters are established and the process parameters are optimized. The experimental results show that the laser process parameters are in the order of the current, defocusing amount, pulse width, and repetition number based on their influence degree on taper and HAZ. In addition, the taper and HAZ thickness are also influenced by the interactive effects of the current and defocusing amount, and the current and pulse width. The established regression equation can describe the relationships between the taper, HAZ thickness and laser process parameters. From the regression equation, the optimized laser process parameters are obtained as follows: 150 A of current, 2 ms of pulse width, 3 of repetition number and 2.18 mm of defocusing amount.

In order to overcome the deficiency of transistors or electronic switches in terahertz band, graphene is used in a terahertz reconfigurable antenna. Based on the model of graphene surface conductivity, the relationships of its surface conductivity to frequency, chemical potential and temperature, and the relationship between surface impedance and chemical potential are analyzed. Analysis of these relathionships proves the advantages of utilizing graphene in reconfigurable antennas. A graphene-based antenna with reconfigurable radiation pattern via applying external biased voltage is designed. The structure consists of a metal dipole (active element) and two metal with graphene dipoles as a reflector and a director. By altering chemical potential (external biased voltage), the states of graphene impedance configured in passive elements are adjusted and their current distribution is changed, which converts the passive ones between a reflector and a director. At last, through simulation and optimization of HFSS, the antenna realizes radiation with directions of 0°，±32°，±37°，±40°, operation frequency in (1.07±0.06) THz, relative impedance bandwidth over 7.84% and the maximum radiation efficiency of 89.96%. The maximum radiation gain has reached up to 8.312 dB at these seven radiation directions. This design has advantages as small size, light weight, simple and stable control, and offers a certain application value to beam-reconfigurable antenna in terahertz.

The phase characteristic of two dimensional hexagonal photonic crystal with near-zero refractive index is investigated by finite-difference time-domain (FDTD) method. A new method to calculate the equivalent refractive index is proposed by using the spatial spectrum of electric field phase. The proposed method can directly reflect the change of the electric field phase, which clarifies the transmission mechanism of the negative refraction. By this method, the influences of the wavelength of transverse magnetic (TM) mode and temperature on equivalent refractive index are studied.

To investigate the treatment effect of new porphyrin photosensitizer PA1 mediated photodynamic antimicrobial chemotherapy (PACT) combined with antibiotics on the rat model with severe massive traumatic infection and the mechanism of the combination treatment, 24 healthy male (clean grade) Wistar rats were used to create the massive trauma infection model. Rats were randomly divided into four groups: model control group, PACT group, antibiotic treatment group and PACT+antibiotic treatment group. There were six rats in each group. The wound healing rate and the number of bacterial colonies were detected at different time points in each experimental group during 8 d treatment. Enzyme-linked immunosorbent assay (ELISA) method was used to detect the expression of basic fibroblast growth factor (bFGF), tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) in the peripheral tissues of the wound. The results show that PACT combined with antibiotic therapy can significantly reduce inflammatory reaction and bacterial colonies in rat trauma tissues, accelerate the wound healing, shorten the wound healing time, increase the content of basic fibroblast factor, and inhibit the expression of inflammatory cytokines TNF-α and IL-6. The treatment effect of PACT combined with antibiotic therapy is better than antibiotic therapy or PACT therapy alone. It suggests that PACT combined with antibiotics can treat large area traumatic infection.

For extracting the blood flow signal of the human skin blood capillary, a combination method of speckle variance (SV) based on the swept source optical coherence tomography, and Doppler algorithm is proposed. This method takes advantage of SV algorithm to get the blood flow signal intensity and advantage of Doppler algorithm to obtain phase. SV algorithm calculates the variance of intensity at the same location of two frames. Doppler algorithm calculates the phase shift between adjacent A scans in order to obtain frequency shift. However, the phase of the swept source output and the sampled signal drift slowly over time, causing the delay between the trigger signal and the subsequent analog to digital conversion to vary within a sample clock cycle. To correct the change in phase, double reference mirrors are used in the experimental system. We adjust the phase shift between adjacent A scans of the two reference mirrors to correct the phase of the corresponding blood flow. Sample simulation experiment and human skin imaging experiment are carried out. SV algorithm is used to obtain the intensity of blood and Doppler phase shift after correction is used to obtain the direction of blood. Blood flow intensity with direction information is obtained by combination of the two methods.

Based on the back-propagation (BP) neural network prediction method and combined with the infrared spectrometer, Raman spectrometer and polarimetry analysis system through the optical fiber, a multi-spectral blood glucose measurement system is developed and a processing method of data fusion is proposed. 30 human blood samples were measured to obtain the optical rotatory dispersion spectrum, infrared spectrum and Raman spectrum, respectively. Spectral data was preprocessed and normalized. The BP neural network model was established to predict the blood glucose content. We use the Clarke error grid analysis to compare the blood glucose content obtained by the three measurement methods and by data fusion. Results show that the fitting precision of the fusion data is 0.9992, and the prediction error is lower than 0.2 mmol/L, which can meet the accuracy of clinic medicine. This method also has high robustness and strong tolerance.

The structure of electronic energy levels is obtained by solving electronic Dirac equation of graphene quantum disks (GQDs) under the infinite-mass boundary conditions. On this basis, the properties of two-photon absorption (TPA) of GQDs are studied theoretically, and the analytical expression of TPA coefficient associated with electron transitions in the conduction band under an arbitrary size-distribution as well as the two-photon transition selection rule are obtained. The research results show that the peak value of TPA coefficient is about 8 orders of magnitude greater than that of conventional semiconductor quantum dots. The energy spectra and TPA spectra can be adjusted and controlled by the GQDs size, size-distribution function and electron relaxation energy.

The face shape design of progressive addition lenses is based on the original vector height model of the lens surface. The key of the design lies on the choice of the meridian curve of the lens. Based on the analysis of surface shape in gradient zone of progressive addition lenses, accurate orientation of the center of curvature of the lens is made. The influence of the gradient curvature on the lens astigmatism and prism degree is analyzed. A design idea of using involute as the meridian of progressive addition lens is presented. The initial vector height model of the surface of the progressive addition lens is established based on the involute as the meridian in gradient area.

An approach of designing polarization-insensitive, broadband spectrum, high-reflectivity mirror based on blocky structure with subwavelength grating is proposed. The reflectance properties of subwavelength grating are determined by structure parameters of grating such as period and duty cycle. Optimizing the period and duty cycle can get a higher reflectivity at broader spectrum. The reflectivities of grating with different periods are calculated by rigorous coupled wave analysis. A set is formed with grating periods of reflectivities over 99%. The size of data set is reduced using an iterative optimization algorithm, which can quickly determine the optimal grating period and the corresponding duty cycle. The simulation results show that two-dimension blocky structure with subwavelength grating mirror fabricated with standard silicon-on-insulator (SOI) wafer can keep the reflectivity over 99% at a spectrum range of 182 nm. Meanwhile the reflectance properties of grating is independent of polarization of vertical incident light. But it can′t keep the reflectivity over 99% at a wavelength range from 1439 nm to 1621 nm anymore as the incident angle up to 7°. So the can be applied on vertical cavity surface emitting lasers (VCSEL) to achieve velocity measurement of laser Doppler or two-dimension network structure of optical buffer. Furthermore, numerical simulations show that the working process of two-dimension blocky structure with subwavelength grating mirror has some tolerance of period and duty cycle.

The electric field analytical expression of Laguerre-Gaussian beam under nonparaxial approximation condition is derived based on the vectorial Rayleigh-Sommerfeld diffraction theory. According to this expression, analytical expressions of the orbital angular momentum density under paraxial and nonparaxial approximation conditions are deduced. Through the numerical simulation, the orbital angular momentum density distribution characteristics under paraxial and nonparaxial approximation conditions are studied, and then the effects of topological charge, waist radius and transmission distance on the orbital angular momentum density distribution are analyzed. It is shown that the orbital angular momentum density distribution under the nonparaxial approximation condition is different from that under the paraxial approximation condition, but the shape of the orbital angular momentum density distribution is close to that under the paraxial approximation with the increase of the topological charge. The result also shows that the topological charge, waist radius and transmission distance do not influence the shape of the orbital angular momentum density distribution under the paraxial approximation condition, while the shape and size of the orbital angular momentum density distribution under the nonparaxial approximation condition are affected by the parameters above.

The dynamical evolution of entanglement between two systems of two-level atoms interacting with a common heat reservoir is investigated and the entanglement between subsystems is described by using the concurrence entanglement. By means of numerical calculations, the effects of initial state and interatomic distance on the two-atom-entanglement evolution as well as the effects of coupling strength and detuning on the two-subsystem-entanglement evolution are analyzed. The results show that, when the interatomic distance is relatively small, the rapid oscillation phenomenon appears no matter whether the initial state is symmetrical state or anti-symmetrical state. The interaction between atoms decreases with the increase of interatomic distance. Under strong coupling, the phenomena of entanglement death and entanglement recovery appear. The entanglement transfer from atoms to heat reservoir is suppressed when the increasing detuning.

In order to evaluate the urban thermal environment of Chengdu city from 1988 to 2013, the land surface temperature and remote sensing images are taken as indexes and data sources. The results show that the high temperature region of urban thermal field migrates outward, and it is transferred to the area between the third ring and circular highway in 2013. The extra-high temperature area decreases year by year, and it is reduced by 1.83 km2 annualy from 2005 to 2013, the areas of high temperature and sub-high temperature increase by 26.90 km2 and 45.35 km2, respectively. The change rule of urban heat island intensity (UHII) is first decrease and then increase and finally decrease in four periods, and the strongest of UHII is 4.37 ℃ in 2005. The UHII is weakened in 1988 and strengthened in 2013 from area of the first ring to circular highway, the maximum values are 5 ℃ and 2.93 ℃ respectively in the two years. The change rules of land surface temperature and vegetation coverage values are fluctuant along the west to east direction with negative correlation, and the certainty factor is 0.5744.

A method for optimizing the space camera system and its parameters is proposed in order to improve the quality of remote sensing images. First, a clamp voltage value is set in the space camera and a largescale array camera for light metering is installed besides the space camera. The image of a certain area can be obtained by metering camera with low and high exposure parameters before the space camera scans this area by the pushbroom mode, and the lowest and the highest luminance information of this area can be measured. Then, exposure parameters of the space camera can be calculated by setting the difference between the highest and the lowest luminance measured as the saturation luminance of the space camera. The value of clamp voltage is set according to the lowest measured luminance. Finally, when the space camera focuses on this area after orbiting to an appropriate position, the space camera images the area with the exposure parameters and the clamp voltage above, and thus the adaptive adjustment of the space camera parameters is realized. Ground experiment results show that the influence of atmosphere on the gray level is removed before imaging and the radiation resolution of the image is improved by optimizing the space camera system. According to the statistical results, the gray range of images increases by 80.7%, and the image entropy also increases significantly. This method makes use of the dynamic range of the imaging system sufficiently based on the current scene, and improves gray level and image quality of the image.

Photonic crystal is a structure with periodic dielectric constant and it has photonic band gap, in which the electromagnetic wave can not propagate in the structure. Two-dimensional slab photonic crystals can be fabricated by etching periodic air holes on a slab substrate, which has been investigated and applied extensively because of their good control of light propagation. Photonic crystal micro-cavities and waveguides can be achieved by introducing defects in the two-dimensional slab photonic crystal. The coupling of micro-cavities and waveguides can be controlled by adjusting geometric parameters, so as to realize the optical devices based on two-dimensional slab photonic crystals such as optical switching, optical storage and single photon source, etc. Properties of the micro-cavities and waveguides of two-dimensional slab photonic crystals are introduced, and their coupling control and potential applications in optical quantum information processing are discussed as well.

Surface plasmons have novel optical properties, such as breaking light diffraction limit, surface localization, and optical near field enhancement, so they have been widely applied in the research area of photovoltaics, photocatalysis and photodetectors. Surface plasmons have excellent light harvesting capability, which can enhance the efficiency of conventional semiconductor devices by integrating with the conventional semiconductor devices. The hot electrons generated from the decay of localized surface plasmons is the core element in converting the incident light to the electrical or chemical energy. Therefore, the study of plasmonic hot electrons generation and relaxation process in microcosm is essential for the design of high-efficiency plasmonic nanophotonic devices. This article reviews the relaxation process of surface plasmons and recent progress in the ultrafast dynamics of plasmonic hot electrons in metal-semiconductor interface, discusses the remained issues and prospects future application of plasmonic hot electrons.

The emergence of optical microscopes opens new doors for the study of cell structures. However, the diffraction limit restricts the detection of fine structures. Recent years, a variety of methods are proposed to overcome the diffraction limit and reach the nanoscale resolution. The nitrogen-vacancy (NV) color center, an important defect in diamond with bright and stable luminescence and long electron spin coherence time, is widely used in quantum computation and quantum measurement. At the same time, it also plays a significant role in super-resolution microscopies. The NV center nanoscale resolution imaging is realized with the combination of all kinds of super resolution imaging microscope, and further the quantum sensor of high spatial resolution is realized. A brief introduction to the structure and the property of NV centers and basic principles of the imaging techniques are given simply. The experimental results of the super-resolution imaging with NV centers are summarized and compared, and finally its applications are summarized and prospected in the future.

The research status and dynamic of single fiber imaging technology are thoroughly discussed. A single multimode optical fiber is used in optical fiber imaging technology. The optical fiber is not only an imaging device, but also an image transmission device. Without scanning devices and imaging lenses, the scene within the fiber view scope can be transmitted from one end to the other end of fiber, so the single optical fiber imaging technology is also called wide-field fiber imaging technology. The technology can reduce the diameter of imaging fiber probe and realize ultrathin endoscopic imaging. The single optical fiber imaging technology burgeoning from holographic optics and Fourier optics is one kind of computation imaging methods, and it includes transmission matrix method and phase compensating method. For multimode fiber, if the transmission matrix in frequency domain or space domain can be obtained in advance, the object image can be recovered from the output light field of fiber, and the wavefront distortion of beam through the fiber can also be measured in advance. The introducing of conjugate phase field of wavefront distortion in the imaging system can eliminate the corresponding phase distortion, and the undistorted object image can be obtained at the output end.

Silicon quantum dots (Si QDs) are usually smaller than 10 nm. They have drawn much attention from researchers because of their novel electronic and optical properties caused by quantum confinement effect and surface effect, which are different from those of bulk silicon materials. In recent years, Si QDs have been applied in the field of optoelectronics because of their novel electronic and optical properties, and a series of research progress have been achieved. The electronic and optical properties of Si QDs are overviewed. The use of Si QDs in optoelectronic devices such as light-emitting diodes, solar cells and photodetectors is introduced in detail. The performance of different types of Si QDs in optoelectronic devices is analyzed as well. It is believed that if continuous efforts in the research on Si QDs are made, Si QDs will play a crucial role in the innovation of optoelectronic devices in the future.

Dried tangerine peels stored for eight different periods were measured by surface-enhanced Raman spectroscopy. Raman spectra on gold film substrate, silver nanoparticle substrate and gold film-silver nanoparticle substrate of dried tangerine peels stored for 11 years were detected and analyzed School. Raman spectra of dried tangerine peels tested on gold film-silver nanoparticle substrate show the most obvious Raman characteristic lines. 12 Raman characteristic peaks at 375, 493, 650 cm-1, etc. were initially assigned, which gave an experimental evidence to judge the biochemical components of dried tangerine peels. Probable enhancing mechanism of the Raman signal of dried tangerine peels on gold film-silver nanoparticle substrate was discussed. By comparing and analyzing the surface-enhanced Raman spectral information, dried tangerine peels of different storage periods were distinguished. According to the Raman spectral information of the eight samples, a conclusion can be drawn that the dried tangerine peels stored for more than 7 years (including 7 years) produce some new components compared with the dried tangerine peels stored for less than 5 years (including 5 years).

The quantitative analysis for plasticizer based on terahertz (THz) time-domain spectroscopy and chemometrics is studied. A novel method for measuring the optical constants of thin liquid samples using THz transmission spectrum is presented. Taking a typical plasticizer, dibutyl phahalate (DBP) as an example, we use the method to determine the refractive index and absorption coefficient of DBP-ethanol and DBP-ethanol-water solutions with different DBP concentrations in THz regime, where a 200 μm path length cuvette is adopted as the sample holder. The results show that the optical constants of DBP-ethanol and DBP-ethanol-water solutions in the terahertz band (0.2-1.1 THz) change regularly corresponding to the DBP content. According to the average refractive index and absorption area the prediction model of DBP concentration in unknown solutions is constructed. The results demonstrate that the THz spectroscopy is a potential method for rapid identification of trace plasticizer in wine or other soft drinks.

NbSiN films are deposited on glass substrates with radio frequency (RF) magnetron sputtering method by taking Nb and Si as targets. The effects of powers of silicon target and niobium target, flow rate of nitrogen and sputtering time on optical properties of films are studied, and the optimal preparation process paremeters are obtained. The test results show that the films are uniformly and compactly deposited under the optimal process paremeters, which mainly compose of NbN, NbSiN, amorphous Si3N4, and little SiO2 and Nb2N2-xO3+x. The optical property analysis shows that the visible light transmissivity of NbSiN films is 90.5% at 550 nm (the most sensitive wavelength for human eyes) and the infrared reflectivity is about 28%, which indicates that the optical property is excellent.

Using the atomic layer deposition technology, the fabrication of TiO2 thin protecting film on silver ornaments with a thickness uniformity less than 3.5% is realized. The X-ray diffraction test results show that the structure of TiO2 thin film is amorphous structure at the deposition temperature of 100 ℃, while the thin film presents anatase phase at the deposition temperature of 250 ℃. The corrosion experiment results show that the TiO2 thin films with the thickness of 30 nm and 45 nm both have the anti-tarnishing ability, while the ability of the latter is better. The spectrum test results show that, under the condition that the appearance of silver ornaments is not affected, the single layer of TiO2 as protecting film is insufficient to achieve the best anti-tarnishing effect.