High dynamic range (HDR) imaging usually produces ghosting artifacts, while the traditional matrix completion (MC) method may fail to completely remove the ghosts, without considering the motion characteris-tics of multi-exposure image. To solve this problem, this paper presents a new HDR imaging method based on content adaptive matrix completion of low dynamic range (LDR) image to remove the ghosts of HDR image. Firstly, according to the image luminance and chrominance information, the LDR image motion area is deter-mined. Then, based on the priori information of motion, the regularization constraint intensity is adjusted in MC process to get each LDR image background information. Finally, a fusion strategy related to multiple exposures is proposed while the difference of details in each image area under different exposures is considered. Regular background sequences and cluttered background sequences are used for experiments. The experimental results demonstrate that, compared with the partial sum minimization of singular values-matrix completion method, the proposed method is more real-time and suitable for cluttered background sequences.

This paper shows some simulation analysis on stitching overlap threshold of strip images for mul-ti-strip stitching model in agile remote sensing imaging. The mission model and geometric degradation model are proposed for multi-strip stitching imaging, and the criterion of overlap region width threshold is presented. Against the nadir strip, we analyze the overlap threshold of different scene types and explore the threshold varia-tion affected by the changes of ground sample distance (GSD). For the agile strip, the effect of pitch angle and roll angle on overlap threshold is analyzed. The simulation result shows that, at 0.46-meter GSD value, the over-lap threshold is more than 28 pixels for 6 scene types, and it is even beyond 31 pixels for the airport and island. The statistical characteristics of threshold perfect match the 3σ guidelines in normal distribution, which has proved the reliability of the solution of overlap threshold. In nadir imaging, GSD has little effect on the overlap pixel threshold at image plane, but has a great effect on overlap distance threshold at ground plane. In agile strip, with larger pitch angle and roll angle, the overlap threshold will increase significantly, which means that the ge-ometric degradation is more powerful to the threshold than the GSD variation. By analyzing the stitching overlap threshold of the strips, we give a meaningful suggestion to the mission planning of high resolution remote sens-ing imaging by agile satellite.

A microfiber strain sensor with arched transition region was demonstrated. By controlling the flame size and tapering speed, a novel micro fiber with arched transition region was successfully fabricated. Consid-erable high order propagation modes of microfiber were excited by the arched transition region, resulting in in-creasing the depth of valley in the transmission spectrum of microfiber. The depth of the transmission valley is up to 18dB. Furthermore, when the axial strain increased, the position of the transmission valley was blue shift, the linearity is 99.15% and the axial strain sensitivity was -13.1 pm/με, which was one order magnitude larger than that of traditional fiber strain sensors based on Bragg grating. This kind of microfiber with arched transition region has many advantages, such as high sensitivity, good mechanical performance, compatibility to traditional optical fiber systems, and easy to be fabricated. It can be widely used in various physical, chemical and biological sens-ing and detection fields.

Linear array sensor S11639 is often used in mini-spectrometer for UV measurement. However, when the exposure volume of S11639 is relatively bigger, the non-linearity of the spectral response will appear. This nonlinear effect will affect the dynamic range of the mini-spectrometer, and therefore, nonlinear correction must be carried out. Photoelectric response of S11639 is measured with halogen tungsten lamp and deuterium lamp to find out the linear part between the exposure and the A/D conversion output, and straight line fitting of the data is made to obtain the factors of S11639 in the linear range. Based on it, the theoretical value in nonlinear range is got by extrapolation, and the difference between the theoretical value and the actual measurement value was calculated. The nonlinear correction of S11639 is realized by polynomial fitting with the least square method. At the same time, compared with the experimental results, the error causes of the experimental data are analyzed, and the experiment is provided for better utilization of mini-spectrometer based on S11639 for photoelectric de-tection in the full dynamic range.

Aiming at the limitations of single sensor in dynamic scene perception issue, an implementation sys-tem for fusing laser and vision was designed. In addition, two improved algorithms were proposed to solve the problems of the error foreground detection in the motion detection and the mismatching between the point clouds of different sensors. As for motion detection, the laser foreground points were firstly detected based on visual background subtraction algorithm. Then, the visual foreground was clustered regarding laser foreground points as the heuristic information. To solve the mismatching of fusion, the laser and vision point cloud were segmented into clusters based on the cell mismatching degree firstly. Then the corresponding stereo point cloud was registered referring to laser clusters. The corrected point cloud could be used for further verification by re-constructing the scene after filtering. The experimental results showed that the fusion foreground obtained finally had a better robustness to shadow. Compared with the whole registration correction, the average mismatching degree reduced by 75%, and the positive ratio in the direction of y and z converged at least 5%.

As a core technique in the video surveillance and 3D map building fields, the moving object detection and scene re-construction are the foundations of the real-time navigation, obstacle avoidance and path planning. In the meantime, as two important sub-problems of environment perception task, they are not only closely connected with the devel-opment of many fields, such as robot, unmanned aircraft, unmanned vehicles and body feeling game, but also are the part of the lives of human intelligence. The current research is mainly based on single laser sensor or single vision sensor. It is difficult to meet the requirements of real-time multi task scenario due to the limitation of the visual field, the amount of data, the richness of the data, the real-time and the anti-jamming. Based on the mutual supplement and constraint of the laser information and the visual information, an implementation system for fusing laser and vision was designed. In addition, two improved algorithms were proposed to solve the problems of the error foreground detection in the motion detection and the mismatching between the point clouds of different sensors.

As a core technique in the video surveillance and 3D map building fields, the moving object detection and scene re-construction are the foundations of the real-time navigation, obstacle avoidance and path planning. In the meantime, as two important sub-problems of environment perception task, they are not only closely connected with the devel-opment of many fields, such as robot, unmanned aircraft, unmanned vehicles and body feeling game, but also are the part of the lives of human intelligence. The current research is mainly based on single laser sensor or single vision sensor. It is difficult to meet the requirements of real-time multi task scenario due to the limitation of the visual field, the amount of data, the richness of the data, the real-time and the anti-jamming. Based on the mutual supplement and constraint of the laser information and the visual information, an implementation system for fusing laser and vision was designed. In addition, two improved algorithms were proposed to solve the problems of the error foreground detection in the motion detection and the mismatching between the point clouds of different sensors.

S11639 is often used in mini-spectrometer for UV measurement. Ideally, each pixel of S11639, in the whole dynamic range, has good linearity between the amount of incident light and signal charge produced by photoelectric conver-sion. However, when the exposure of S11639 is bigger, the nonlinearity of S11639 photoelectric response will appear. The nonlinearity of S11639 is related to its structure, because sharing and diffusion of the pixel potential wells occur in the photosensitive area, and the charge interaction enhances more with the increase of the exposure, and even leads to charge overflow. So the more the exposure, the worse the linearity of S11639. The nonlinearity of the S11639 photoelectric response affects the dynamic range of the spectrometer. S11639 is applied in mini-spectrometer which has its own light dispersion system. Halogen tungsten lamp and deuterium lamp are compensated to light from the ultraviolet to the near infrared range of 215 nm~2500 nm. The light is injected through the optical fiber to spectrom-eter with this light source. The composite light passing asymmetric C-T optical system is decomposed into mono-chromatic light which is shined on the surface of S11639. The signal is amplified linearly and converted by A/D converter, and the output of A/D conversion is a function of the exposure. Photoelectric response of S11639 is measured to find out the relations between the exposure and the A/D conversion output in the multi wavelength po-sitions of S11639. The conclusion is described below: If the A/D initial output values are the same in different wavelength positions by adjusting the light intensity, the integral time is changed at the same step, and the changes of A/D output value are still the same, so only a photoelectric response curve is measured at one wavelength position, which is suitable for other wavelengths. By changing the integration time of the spectrometer at one wavelength po-sition, the exposure of S11639 is changed, and the value of the A/D conversion is obtained. Straight line fitting of the data is made to obtain the factors of S11639 in the linear range of one wavelength position. Extrapolating from the linear part will reach the theoretical values in nonlinear range, and we can calculate the differences between the ac-tual measurement values and the theoretical values. The polynomial fitting with least squares method realizes the nonlinear correction of S11639 at one wavelength position. Since the coefficients of the linear fitting are the same at different wavelengths, they can be applied to nonlinear correction at other wavelengths. At the same time, compared with the experimental results, the error causes of the experimental data are analyzed, and the experiment is provided for better utilization of mini-spectrometer based on S11639 for photoelectric detection in the full dynamic range.

S11639 is often used in mini-spectrometer for UV measurement. Ideally, each pixel of S11639, in the whole dynamic range, has good linearity between the amount of incident light and signal charge produced by photoelectric conver-sion. However, when the exposure of S11639 is bigger, the nonlinearity of S11639 photoelectric response will appear. The nonlinearity of S11639 is related to its structure, because sharing and diffusion of the pixel potential wells occur in the photosensitive area, and the charge interaction enhances more with the increase of the exposure, and even leads to charge overflow. So the more the exposure, the worse the linearity of S11639. The nonlinearity of the S11639 photoelectric response affects the dynamic range of the spectrometer. S11639 is applied in mini-spectrometer which has its own light dispersion system. Halogen tungsten lamp and deuterium lamp are compensated to light from the ultraviolet to the near infrared range of 215 nm~2500 nm. The light is injected through the optical fiber to spectrom-eter with this light source. The composite light passing asymmetric C-T optical system is decomposed into mono-chromatic light which is shined on the surface of S11639. The signal is amplified linearly and converted by A/D converter, and the output of A/D conversion is a function of the exposure. Photoelectric response of S11639 is measured to find out the relations between the exposure and the A/D conversion output in the multi wavelength po-sitions of S11639. The conclusion is described below: If the A/D initial output values are the same in different wavelength positions by adjusting the light intensity, the integral time is changed at the same step, and the changes of A/D output value are still the same, so only a photoelectric response curve is measured at one wavelength position, which is suitable for other wavelengths. By changing the integration time of the spectrometer at one wavelength po-sition, the exposure of S11639 is changed, and the value of the A/D conversion is obtained. Straight line fitting of the data is made to obtain the factors of S11639 in the linear range of one wavelength position. Extrapolating from the linear part will reach the theoretical values in nonlinear range, and we can calculate the differences between the ac-tual measurement values and the theoretical values. The polynomial fitting with least squares method realizes the nonlinear correction of S11639 at one wavelength position. Since the coefficients of the linear fitting are the same at different wavelengths, they can be applied to nonlinear correction at other wavelengths. At the same time, compared with the experimental results, the error causes of the experimental data are analyzed, and the experiment is provided for better utilization of mini-spectrometer based on S11639 for photoelectric detection in the full dynamic range.

S11639 is often used in mini-spectrometer for UV measurement. Ideally, each pixel of S11639, in the whole dynamic range, has good linearity between the amount of incident light and signal charge produced by photoelectric conver-sion. However, when the exposure of S11639 is bigger, the nonlinearity of S11639 photoelectric response will appear. The nonlinearity of S11639 is related to its structure, because sharing and diffusion of the pixel potential wells occur in the photosensitive area, and the charge interaction enhances more with the increase of the exposure, and even leads to charge overflow. So the more the exposure, the worse the linearity of S11639. The nonlinearity of the S11639 photoelectric response affects the dynamic range of the spectrometer. S11639 is applied in mini-spectrometer which has its own light dispersion system. Halogen tungsten lamp and deuterium lamp are compensated to light from the ultraviolet to the near infrared range of 215 nm~2500 nm. The light is injected through the optical fiber to spectrom-eter with this light source. The composite light passing asymmetric C-T optical system is decomposed into mono-chromatic light which is shined on the surface of S11639. The signal is amplified linearly and converted by A/D converter, and the output of A/D conversion is a function of the exposure. Photoelectric response of S11639 is measured to find out the relations between the exposure and the A/D conversion output in the multi wavelength po-sitions of S11639. The conclusion is described below: If the A/D initial output values are the same in different wavelength positions by adjusting the light intensity, the integral time is changed at the same step, and the changes of A/D output value are still the same, so only a photoelectric response curve is measured at one wavelength position, which is suitable for other wavelengths. By changing the integration time of the spectrometer at one wavelength po-sition, the exposure of S11639 is changed, and the value of the A/D conversion is obtained. Straight line fitting of the data is made to obtain the factors of S11639 in the linear range of one wavelength position. Extrapolating from the linear part will reach the theoretical values in nonlinear range, and we can calculate the differences between the ac-tual measurement values and the theoretical values. The polynomial fitting with least squares method realizes the nonlinear correction of S11639 at one wavelength position. Since the coefficients of the linear fitting are the same at different wavelengths, they can be applied to nonlinear correction at other wavelengths. At the same time, compared with the experimental results, the error causes of the experimental data are analyzed, and the experiment is provided for better utilization of mini-spectrometer based on S11639 for photoelectric detection in the full dynamic range.

Strain sensing is of major importance for applications of monitoring to buildings, bridges and many other mechani-cal structures. The traditional strain sensor cannot meet the requirements of long-term monitoring of these engineering structures due to its poor immunity to electromagnetic interference, poor water resistance and its own zero-drift defect. With many advantages such as being compact, immunity to electromagnetic interference, and high sensitivity, the optical fiber strain sensor was a good candidate for the strain sensing.

The measurement system based on optical interference has obvious advantages of high precision and high sensi-tivity. However, the signal is easy to be disturbed by vibration from environment, so the system needs to stay away from the vibration source. To use the optical interference method for real-time measurement, it has to im-prove the system’s stability. We proposed an integrated Michelson interference device to measure the thicknesses of multiple layers of optical plate, which could improve the stability of the optical interference system in a new way. Optical cement is used to splice the glass modules, which could eliminate the influence of the glue. The ma-terial with low thermal expansion coefficient was used in a symmetrical structure, so that the device can make compensation to the environmental temperature variation. And the input and output ports were welded into the packaging box. Through these smart design and high precision processing technique, the light path of the structure was integrated into a whole, so the device won’t be disturbed by the environment compared to the other interfer-ometers during measurement. To test the stability of the device, a low coherent interferometry system was intro-duced, and an interferogram with ~3 kHz speed was acquired. Compared with a fiber based interferometer, it was found that our system had obviously more stable signal. We also used the low coherent interferometry system to demonstrate the method of multiple layers measurement, and the principle was given. The broadband light source is used as the input, the signals reflected from sample and the reference beams were combined and the output in-terference signal was exported to a synchronous acquisition system. And then the fast Fourier transform algorithm was used to analyze the interference signal. The precision of our low coherent interferometry system was 8.57 μm, and the measurement range was 5 mm in air. Finally, the thicknesses of a glass slide and a stack of two cover glasses were measured to confirm its feasibility to do the real-time measurement. The measured thickness of the glass slide was 2230.8 μm, the two cover glasses were 181.6 μm and 175.1 μm, respectively. The measurement was comparable with the commercial thickness measurement equipment. The results by high precision imaging measuring instrument VMS-1510 were 2225 μm, 178 μm and 173 μm, respectively. And the results from microm-eter were 2221 μm, 172 μm and 170 μm, respectively. Furthermore, we could also give the thickness of the air gap between the two cover glasses, which was 19.6 μm. In summary, we believe this device and method will be help-ful for the real-time interference measurement of multiple layers of optical plates.

The measurement system based on optical interference has obvious advantages of high precision and high sensi-tivity. However, the signal is easy to be disturbed by vibration from environment, so the system needs to stay away from the vibration source. To use the optical interference method for real-time measurement, it has to im-prove the system’s stability. We proposed an integrated Michelson interference device to measure the thicknesses of multiple layers of optical plate, which could improve the stability of the optical interference system in a new way. Optical cement is used to splice the glass modules, which could eliminate the influence of the glue. The ma-terial with low thermal expansion coefficient was used in a symmetrical structure, so that the device can make compensation to the environmental temperature variation. And the input and output ports were welded into the packaging box. Through these smart design and high precision processing technique, the light path of the structure was integrated into a whole, so the device won’t be disturbed by the environment compared to the other interfer-ometers during measurement. To test the stability of the device, a low coherent interferometry system was intro-duced, and an interferogram with ~3 kHz speed was acquired. Compared with a fiber based interferometer, it was found that our system had obviously more stable signal. We also used the low coherent interferometry system to demonstrate the method of multiple layers measurement, and the principle was given. The broadband light source is used as the input, the signals reflected from sample and the reference beams were combined and the output in-terference signal was exported to a synchronous acquisition system. And then the fast Fourier transform algorithm was used to analyze the interference signal. The precision of our low coherent interferometry system was 8.57 μm, and the measurement range was 5 mm in air. Finally, the thicknesses of a glass slide and a stack of two cover glasses were measured to confirm its feasibility to do the real-time measurement. The measured thickness of the glass slide was 2230.8 μm, the two cover glasses were 181.6 μm and 175.1 μm, respectively. The measurement was comparable with the commercial thickness measurement equipment. The results by high precision imaging measuring instrument VMS-1510 were 2225 μm, 178 μm and 173 μm, respectively. And the results from microm-eter were 2221 μm, 172 μm and 170 μm, respectively. Furthermore, we could also give the thickness of the air gap between the two cover glasses, which was 19.6 μm. In summary, we believe this device and method will be help-ful for the real-time interference measurement of multiple layers of optical plates.

Point pixel enhancement algorithm is an important preprocessing technique in automatic point recognition and de-tection systems. The point pixel in the image of the pixels are small, lacking information such as shape and texture, of low signal noise ratio, and easily submerged in the complex background, which is extremely unfavorable for sub-sequent extraction and detection. So point enhancement is necessary.

Point pixel enhancement algorithm is an important preprocessing technique in automatic point recognition and de-tection systems. The point pixel in the image of the pixels are small, lacking information such as shape and texture, of low signal noise ratio, and easily submerged in the complex background, which is extremely unfavorable for sub-sequent extraction and detection. So point enhancement is necessary.

Polarization is the important feature of reflected light from object (including wavelength, amplitude, phase, and po-larization). According to the Fresnel reflection law, polarized characteristic will occur within the reflecting effect or radiating effect, which is the foundation for polarization remote sensing. Especially, man-made objects typically produce relatively strong polarization reflection signatures compared to natural materials. Theses signatures can be exploited for target or image contrast enhancement. Airborne imaging polarimeter is one of the important research techniques in the remote sensing fields which could be used to further describe the surface roughness, texture direc-tion and surface orientation of the interesting object, especially for the recognition of object contour and surface roughness.

Polarization is the important feature of reflected light from object (including wavelength, amplitude, phase, and po-larization). According to the Fresnel reflection law, polarized characteristic will occur within the reflecting effect or radiating effect, which is the foundation for polarization remote sensing. Especially, man-made objects typically produce relatively strong polarization reflection signatures compared to natural materials. Theses signatures can be exploited for target or image contrast enhancement. Airborne imaging polarimeter is one of the important research techniques in the remote sensing fields which could be used to further describe the surface roughness, texture direc-tion and surface orientation of the interesting object, especially for the recognition of object contour and surface roughness.

This paper shows some simulation analysis on stitching overlap threshold of strip images for multi-strip stitching model in agile remote sensing imaging. To realize the high spatial resolution and high time resolution at the same time, agile satellites have been used more frequently. Besides the maneuverability of satellite attitude adjustment, the mission planning is the key to the efficiency of high resolution optical imaging. Thus, our purpose is to find the suitable stitching overlap width between two adjacent strips. Lower threshold will sacrifice the stitching quality of remote sensing image, while higher threshold will cause an inefficient imaging mission. The mission model and geometric degradation model are proposed for multi-strip stitching imaging, and the criterion of overlap region width threshold is presented. We use scale-invariant feature transform (SIFT) detector for image registration and random sample consensus (RANSAC) to eliminate the outliers. Besides the root-mean-square error (RMSE) of feature points in overlap region, the RMSE of four corner points and all pixel points of overlap region are considered. When all these three RMSE are less than 1 pixel, the overlap threshold is confirmed.

This paper shows some simulation analysis on stitching overlap threshold of strip images for multi-strip stitching model in agile remote sensing imaging. To realize the high spatial resolution and high time resolution at the same time, agile satellites have been used more frequently. Besides the maneuverability of satellite attitude adjustment, the mission planning is the key to the efficiency of high resolution optical imaging. Thus, our purpose is to find the suitable stitching overlap width between two adjacent strips. Lower threshold will sacrifice the stitching quality of remote sensing image, while higher threshold will cause an inefficient imaging mission. The mission model and geometric degradation model are proposed for multi-strip stitching imaging, and the criterion of overlap region width threshold is presented. We use scale-invariant feature transform (SIFT) detector for image registration and random sample consensus (RANSAC) to eliminate the outliers. Besides the root-mean-square error (RMSE) of feature points in overlap region, the RMSE of four corner points and all pixel points of overlap region are considered. When all these three RMSE are less than 1 pixel, the overlap threshold is confirmed.

This paper shows some simulation analysis on stitching overlap threshold of strip images for multi-strip stitching model in agile remote sensing imaging. To realize the high spatial resolution and high time resolution at the same time, agile satellites have been used more frequently. Besides the maneuverability of satellite attitude adjustment, the mission planning is the key to the efficiency of high resolution optical imaging. Thus, our purpose is to find the suitable stitching overlap width between two adjacent strips. Lower threshold will sacrifice the stitching quality of remote sensing image, while higher threshold will cause an inefficient imaging mission. The mission model and geometric degradation model are proposed for multi-strip stitching imaging, and the criterion of overlap region width threshold is presented. We use scale-invariant feature transform (SIFT) detector for image registration and random sample consensus (RANSAC) to eliminate the outliers. Besides the root-mean-square error (RMSE) of feature points in overlap region, the RMSE of four corner points and all pixel points of overlap region are considered. When all these three RMSE are less than 1 pixel, the overlap threshold is confirmed.

High dynamic range (HDR) image is more consistent with human perception, and is being applied to many fields, such as consumer electronics, remote sensing system, intelligent transportation, security monitoring. So far, HDR imaging has usually produced ghosting artifacts, so there are many researchers carrying out the research about de-ghosting. Some researchers came up with the algorithms which can remove ghosts by detecting moving regions, and other researchers considered the fusion weight distribution to eliminate the artifacts. Recently, the algorithm that models the HDR imaging problem as a rank minimization problem is proposed. It is solved with the idea of ma-trix completion (MC). However, as no attention was paid to the motion characteristics of multi-exposure image, the traditional MC method could fail to completely remove the ghosts. Therefore, in order to solve this problem, ac-cording to the motion information of multi-exposure images and fusion strategy related to exposures, this paper presents a new HDR imaging method based on content adaptive MC of low dynamic range (LDR) image to remove the ghosts of HDR image. Firstly, the motion area of LDR image is obtained based on the luminance and color infor-mation of the image with the median threshold bitmap (MTB) features, the hue feature H and color saturation char-acteristics S. Then, based on the priori information of motion, regularization strength is adjusted in the MC process to obtain the low-rank background information of each LDR image. Finally, a fusion strategy related to multiple ex-posures is proposed to achieve a ghost-free HDR image, while the difference of details in each image area under dif-ferent exposures is considered. Regular background sequences and cluttered background sequences are used for ex-periments. The experimental results demonstrate that, compared with the partial sum minimization of singular val-ues-matrix completion method, the proposed method is more real-time and suitable for cluttered background se-quences. The above figure is part of the experimental results, where (e) and (h) are the results of the proposed algo-rithm of Arch and Forest sequences. Compared with these algorithms, the images synthesized by the proposed algo-rithm not only have no ghost, but also have richer details. In addition, by calculating the processing speed of several classical algorithms and the proposed algorithm, it is shown that the proposed algorithm can reduce the computa-tional complexity of the overall HDR imaging operation and run more efficiently.

Color filters are useful for image sensors, display devices, and many other applications. Traditional color filters use colorant-based materials to achieve a desired color spectrum, which transmit a particular color while absorbing the undesired surrounding spectrum under white light illumination. Problems with colorant-based filters include low transmission efficiency, heating due to absorption of light, and imperfect color purity. Technologies to improve color filter have led to researches on diffractive gratings color filters. The guided-mode resonance filter (GMRF) is a sig-nificant candidate for a wide variety of applications because of its feasible of fabrication and super wave-length-selecting ability. The GMRFs with different resonance wavelengths are feasibility to be integrated on the same substrate by changing the grating period. However, the reflectance of a 1-D grating structure depends greatly on po-larization modes of the incident light, and the resonance wavelength of TE polarized light is generally different from that of TM polarized light. As natural light can be considered as the superposition of TE polarization and TM polari-zation, the reflection spectra for both TE and TM polarizations are different. Thus the color of reflected light from a 1-D GMRF is a combination of TE and TM polarizations, and the reflected light becomes partially polarized light. Unfortunately, previous research results can not weaken reflectance from TE and TM polarizations by altering the period of GMRFs. The characteristics of light polarization and color reflected by a 1-D GMRF are studied. By numer-ical calculations and simulations using the finite difference time domain (FDTD) method, a triple-layer GMRF is de-signed under non-polarized light illumination. Further researches show that the reflectance spectra of TE polariza-tion and TM polarization can be changed by altering the fill factor of the GMRF. After the reflectance spectra of TE polarization and TM polarization of the GMRF are calculated by using the FDTD method, mixed color of TE and TM reflection spectra can be studied by the chromaticity theory. The color of the reflected light can be calculated by RGB values and we can find that the reflected light color becomes pure when f is 0.9. Moreover, by calculating the polari-zation degree of the reflected light, we find that the polarization degree drops to 0.1 or lower when f is larger than 0.5. The results show that the color and polarization degree of the reflected light from a GMRF are tunable by altering the fill factor. The results can provide references for the design and fabrication of GMRF.

For ground-based exoplanet imaging, atmosphere turbulence is changing from time to time, which induces speckle noise and hampers the high-contrast imaging of the faint exoplanets. We propose a differential-imaging polarimeter dedicated for exoplanet high-contrast imaging. The system contains a zero-order half-wave plate (HWP) located on the optical pupil plane, which can rotate to modulate the incoming light, and a Wollaston prism (WP) is used to gen-erate two polarized images, which is used for simultaneously polarization differential imaging and thus our system is fundamentally immune to the atmospheric turbulence induced temporally-variable wavefront aberration. For the star image is much brighter than that of the exoplanet, the exoplanet image cannot be seen before the polarimeter. Since starlight is in generally unpolarized, while exoplanet light is somehow polarized, we focus our discussions on the subtraction of the on-axis starlight, which will automatically result in an extraction of the polarized exoplanet light. However, the direction subtraction of the left side and right side image cannot yield a good result. For example, the intensity difference in both side beams limits the performance of such subtraction. In addition, the image distor-tion, which will result in a difference for the star point spread functions (PSFs) on both sides, will also seriously limit the subtraction. Therefore, in order to achieve best differential-imaging performance, we also propose an eight-variable optimization algorithm, which is proven to be able to effectively correct the distortion and the inten-sity unbalance between the two differential images. Laboratory experiments indicate that the proposed polarimeter combined with the optimization algorithm successfully achieves an extra contrast of about 30~50 times in a close angular distance in the region of 3λ/D~5λ/D, and the contrast improvement throughout the region of small angular distance by the polarimeter is apparent. The experimental results demonstrate that our polarimeter works well for both perpendicular polarization components. In conclusion, our polarimeter has the following advantages: 1) The system is simple and compact, which is different from the traditional polarimeter that employs the mechanical modulation approach; 2) Image distortion and intensity unbalance are considered and optimized for best contrast performance; 3) Most important, each polarization component is measurement simultaneously, which is fundamen-tally immune to the rapidly-changed atmospheric turbulence induced speckle noise. The work is demonstrated to be a promising technique, since our polarimeter has the potential to achieve an overall contrast better than 10-8 when used with current extreme adaptive optics and coronagraph systems, and such work is critical to achieve the scien-tific goal toward the direct imaging of giant Jupiter-like exoplanets for a ground-based telescope.

In the field of parts cutting, compared with the traditional mechanical cutting and high-pressure water jet cutting, laser cutting has significant superiorities in processing efficiency, precision and environmental protection. However, the thermal damage on the material caused by laser cutting will affect the performance and working life of the parts which limits the development of laser cutting. In order to solve this problem, water-jet guided laser cutting technol-ogy is invented. Water-jet guided laser cutting technology is a composite processing method which uses the water jet to guide the laser beam for cutting the workpiece. For the difference between the refractive indexes of water and air, when the laser beam passes through the water and air interface at a certain angle, the laser will be totally reflected without refraction if the incident angle is less than the total reflection critical angle. This phenomenon can be utilized to propagate the laser in the water jet and guide it to the machined surface for cutting. The advantages of this tech-nology are small heat affected zone, high precision, no pollution and so on. Because of the superiorities of the wa-ter-jet guided laser cutting technology, the domestic and international researchers are increasingly interested in the relevant principles and key technology of the water-jet guided laser cutting. Their researches provided theoretical basis of the water-jet guided laser which promotes its development and application. The domestic and international research progress of water-jet guided laser cutting is reviewed from two aspects: theory and process. For example, Li Ling studied the water-jet guided laser technology by the experiment, finding the relationship about the laser energy attenuation and water jet stability. Besides, the cutting parameters about pulse energy, processing speed, and working distance for processing silicon were also optimized. The processed silicon wafer has little burrs, cracks, heat affect-ed zone, and the surface quality is good. At last, the development status of water-jet guided laser equipment is sum-marized. The future development direction of the water-jet guided laser cutting is larger energy and finer water jet. But at the current stage of research, there are many technical difficulties in terms of nozzle orifice manufacture, cou-pling control system and process research. In the future, theoretical and experimental researches on water-jet guided laser cutting should be studied to accelerate the development of equipment and reduce the gap between the domestic and abroad.

In the field of parts cutting, compared with the traditional mechanical cutting and high-pressure water jet cutting, laser cutting has significant superiorities in processing efficiency, precision and environmental protection. However, the thermal damage on the material caused by laser cutting will affect the performance and working life of the parts which limits the development of laser cutting. In order to solve this problem, water-jet guided laser cutting technol-ogy is invented. Water-jet guided laser cutting technology is a composite processing method which uses the water jet to guide the laser beam for cutting the workpiece. For the difference between the refractive indexes of water and air, when the laser beam passes through the water and air interface at a certain angle, the laser will be totally reflected without refraction if the incident angle is less than the total reflection critical angle. This phenomenon can be utilized to propagate the laser in the water jet and guide it to the machined surface for cutting. The advantages of this tech-nology are small heat affected zone, high precision, no pollution and so on. Because of the superiorities of the wa-ter-jet guided laser cutting technology, the domestic and international researchers are increasingly interested in the relevant principles and key technology of the water-jet guided laser cutting. Their researches provided theoretical basis of the water-jet guided laser which promotes its development and application. The domestic and international research progress of water-jet guided laser cutting is reviewed from two aspects: theory and process. For example, Li Ling studied the water-jet guided laser technology by the experiment, finding the relationship about the laser energy attenuation and water jet stability. Besides, the cutting parameters about pulse energy, processing speed, and working distance for processing silicon were also optimized. The processed silicon wafer has little burrs, cracks, heat affect-ed zone, and the surface quality is good. At last, the development status of water-jet guided laser equipment is sum-marized. The future development direction of the water-jet guided laser cutting is larger energy and finer water jet. But at the current stage of research, there are many technical difficulties in terms of nozzle orifice manufacture, cou-pling control system and process research. In the future, theoretical and experimental researches on water-jet guided laser cutting should be studied to accelerate the development of equipment and reduce the gap between the domestic and abroad.

In the field of parts cutting, compared with the traditional mechanical cutting and high-pressure water jet cutting, laser cutting has significant superiorities in processing efficiency, precision and environmental protection. However, the thermal damage on the material caused by laser cutting will affect the performance and working life of the parts which limits the development of laser cutting. In order to solve this problem, water-jet guided laser cutting technol-ogy is invented. Water-jet guided laser cutting technology is a composite processing method which uses the water jet to guide the laser beam for cutting the workpiece. For the difference between the refractive indexes of water and air, when the laser beam passes through the water and air interface at a certain angle, the laser will be totally reflected without refraction if the incident angle is less than the total reflection critical angle. This phenomenon can be utilized to propagate the laser in the water jet and guide it to the machined surface for cutting. The advantages of this tech-nology are small heat affected zone, high precision, no pollution and so on. Because of the superiorities of the wa-ter-jet guided laser cutting technology, the domestic and international researchers are increasingly interested in the relevant principles and key technology of the water-jet guided laser cutting. Their researches provided theoretical basis of the water-jet guided laser which promotes its development and application. The domestic and international research progress of water-jet guided laser cutting is reviewed from two aspects: theory and process. For example, Li Ling studied the water-jet guided laser technology by the experiment, finding the relationship about the laser energy attenuation and water jet stability. Besides, the cutting parameters about pulse energy, processing speed, and working distance for processing silicon were also optimized. The processed silicon wafer has little burrs, cracks, heat affect-ed zone, and the surface quality is good. At last, the development status of water-jet guided laser equipment is sum-marized. The future development direction of the water-jet guided laser cutting is larger energy and finer water jet. But at the current stage of research, there are many technical difficulties in terms of nozzle orifice manufacture, cou-pling control system and process research. In the future, theoretical and experimental researches on water-jet guided laser cutting should be studied to accelerate the development of equipment and reduce the gap between the domestic and abroad.

Although current state-of-the-art ultrafast video-se-quence two-dimensional imaging methods are capable of capturing a single event with frame rates up to 1? THz, they lack the ability to illuminate samples at arbitrary wavelengths and/or to detect spectrally complex sig-nals, thus preventing these methods from being com-patible with most spectroscopic approaches to extract species- specific information or quantum state dynam-ics.

The high energy proton beam has a unique Prague peak, which means that the proton loses little energy on the transmission path and the energy is mainly deposited at the end. Therefore, the applications of high energy proton beam in the treatment of cancer in vivo, while killing cancer cells, can well protect the healthy cells. This treatment is called proton knife. Traditional ac-celerator proton knife tumor therapy has made pro-gress at home and abroad, and the clinical effect is good, but the cost of treatment is expensive and difficult to be popularized.

Same as the electron, the photon also carries spin an-gular momentum (SAM) and orbital angular momentum (OAM). OAM beams have many applications in the field of classical and quantum optics, such as optical and quantum communications, particle manipulation, su-per-resolution imaging, and so forth. Traditional ele-ments for optical OAM generation are bulky and heavy, and have no spin-orbit interactions (SOIs). The metasurfaces based on geometric phase allow symmet-ric SOIs, however, the symmetry limits the applications of SOIs.