2016 Vol. 45, No. S2
column
- Laser technology and application
- Laser radar technology
- Photoelectric measurement
- Space debris detection
- Advanced optical material
- Advanced optical materials
- Photoelectric devices and microsystem
- Optical design and simulation
- Spectrum detection and analysis
- Information acquisition and identification
The continuous-wave (CW) mode-locking laser pumping intra-cavity optical parametric oscillator (OPO) was realized with experiment, output of mid-infrared idle light was gotten. The cavity shape, position of cavity mirror, cavity length were determined by ABCD matrix considering stable cavity. By matching the length of the OPO cavity and the fundamental frequency laser cavity to meet pumping condition synchronously. Firstly, the output profile of SESAM mode-locking laser was measured without OPO oscillating, the threshold of stable continuous-wave mode-locking running was found. Secondly, output power, output waveform, repetition frequency, and pulse width of the idle frequency, signal and fundamental frequency light of intra-cavity OPO were also measured. It is concluded that the central wavelength of the idle frequency light is about 3.3m through measuring spectrum of signal light and fundamental frequency light.
2016, 45(S2): 5-10.
doi: 10.3788/IRLA201645.S206002
To research the thrust or impulse characteristics of the laser micro-thruster working in multi-pulse mode, the response characteristics of the torsional balance responding to multi-pulse force was analyzed. The measurement method of average thrust or impulse for multi-pulse force was brought forward, and the influence on the measurement of the frequency of the pulse force and when the pulse force was not standard periodic pulse was analyzed by simulation. The results demonstrate that the average thrust is determined as a function of the average equilibrium when the repetitive frequency of pulse force is much higher than the natural frequency such as 10 times. The impulse is determined as a function of the maximum peak and the angle before the maximum peak time when the period of the balance is longer than the working time of multi-pulse force. And when the multi-pulse force is not standard period pulse, the method above is effective.
2016, 45(S2): 11-14.
doi: 10.3788/IRLA201645.S206003
The new designed fiber end-pump coupling device was reported to solve the problem in a monolithic fiber system outputting higher level of signal power, which was limited by pump brightness and temperature control of the pump injection area. By enlarging the signal fiber cladding diameter, more pump power could be injected in fiber system and the temperature of the pump injection area was successfully reduced. In experiment, 9.95 kW pump laser was injected to a monolithic fiber laser system, and over 6 kW signal output was realized. This fiber end-pump coupling device is capable of 10 kW class pump injection and promising for the application in a 10 kW class monolithic fiber laser system.
2016, 45(S2): 15-18.
doi: 10.3788/IRLA201645.S206004
High power fiber laser requires high brightness and power fiber coupled laser diode module as pumping source. A multi-single emitter diode with high brightness and power was developed by precision assembling and beam combining technology. 14 laser diodes beam were coupled into a core diameter of 105 m, numerical aperture (NA) 0.22 fiber via spatial combination and polarization combination. Experiment results show that the optical power from fiber can reach to 120 W with a brightness of 9.1 MW/(cm2sr), and the electoral to optical efficiency is 45%, when operating current is 12 A.
2016, 45(S2): 19-25.
doi: 10.3788/IRLA201645.S230001
The middle atmospheric density, pressure and temperature structure was measured by 532 nm and 355 nm Rayleigh Scattering Lidar between the altitude 25 km and 40 km at Hefei(31.90N; 117.170E), respectively. 532 nm Rayleigh Scattering Lidar system adopted Nd:YAG laser of 532 nm and 400 mm Cassegrain telescope. 355 nm Rayleigh Scattering Lidar system which was improved on the basis of 532 nm Rayleigh Scattering Lidar system, employed Nd:YAG laser of 355 nm and four Cassegrain telescopes of 400 mm. According to experimental comparison, it could obtain that the SNR of 355 nm Rayleigh Scattering Lidar is more than 532 nm Rayleigh Scattering Lidar of about 6 times. The fluctuation of the density ratio and pressure ratio of 355 nm Rayleigh Scattering Lidar to Sounding Balloon are less than the fluctuation of 532 nm Rayleigh Scattering Lidar. The temperature biases between 355 nm Rayleigh Scattering Lidar and the sounding balloon of that day are about -2.14 K, and the maximum deviation is about 6 K. And the temperature biases between 532 nm Rayleigh Scattering Lidar and the sounding balloon of that day are about -6.98 K, and the maximum deviation is about 9 K. The results of comparative test for 355 nm Rayleigh Scattering Lidar and 532 nm Rayleigh Scattering Lidar have shown that the detection precision of 355 nm Rayleigh Scattering Lidar was higher than 532 nm Rayleigh Scattering Lidar, and the performance of 532 nm Rayleigh Lidar is better than 532 nm Rayleigh Lidar.
2016, 45(S2): 26-29.
doi: 10.3788/IRLA201645.S217001
Isoplanatic angle is one of important optical turbulence parameter which has played a significant role in the design of adaptive optics system and the analysis of compensation effect. An apodized mask with triple concentric annuluses was introduced, Measuring principle, measuring method and main specifications were introduced in this paper about the high precision isoplanatic angle. Next to the Xinjiang region, the measurement experiment of isoplanatic angle was carried out, and was compared with single ring isoplanatic angel measuring instrument. The results show that two sets of instruments measured such as isoplanatic angle trends are basically identical. The triple concentric mirror can better modulate the light intensity to match the weight demand of the isoplanatic angle measurement with altitude. The error of the fitting coefficient is small, and it can realize the high precision measurement of the isoplanatic angle.
2016, 45(S2): 30-34.
doi: 10.3788/IRLA201645.S229001
Two-Line Elements(TLE) datasets are the primary source for debris orbits. However, the orbit prediction precision for low earth orbiting space debris using the TLE-SGP4 model is far less than satisfactory. The method of orbit prediction by combining multiple TLE can achieve the purpose of improving orbit predication precision for low earth orbiting space debris. Firstly, this method determined the debris orbit using the TLE-computed positions near the TLE reference epochs as pseudo-observations in the orbit determination, and then to propagate the orbit. The method was tested by continuous TLE data on 5 debris objects at altitude of about 500-600 km during 2009. The orbit prediction results for the method and TLE-SGP4 model were compared using updated TLE data as reference orbit. The 10-day orbit prediction errors for the 5 debris are all less than 5 km using this method, which is significantly less than those from using the TLE-SGP4 model.
2016, 45(S2): 35-40.
doi: 10.3788/IRLA201645.S229002
In order to monitor the space debris effectively, on the basis of 60 cm satellite laser ranging (SLR) system, the high repetition space debris laser ranging system was established with the multiple technologies, such as the real-time modification of time offset, the closed-loop tracking of debris target, the direction control of laser beam, the real-time correction of satellite forecast and so on, which was colocation observed at space SLR system. In 26 observation days, 466 passes and 26 passes in twilight were acquired, the observed elevation from 19 to 87 degree, ranging accuracy about 1 m, range from 400 km to 1 800 km, the minimum RCS can achieve to be 0.9 m2. By comparing with results from other observatories, the high repetition frequency rate DLR system has high precision, large observation range, small RCS, and more echo data, and the observed data is stable and reliable, which has reached the international advanced level.
2016, 45(S2): 41-47.
doi: 10.3788/IRLA201645.S229003
Using the way of laser in centimeter orbital debris detection has been the hot research topic. According to space based laser detection system, a basic model of centimeter orbital debris detection was established, with selecting a particular wavelength laser, space-based platform orbital parameter and position mode of detector to reduce background noise realizing once successful detection. The relationship between the detection range, the size of debris and detection probability, the minimum detection power and the furthest distance of the system was discussed. By changing the diameter of orbital debris and laser average power, the study of effect on detection range was discussed in detail. The researches show that under the existing conditions, it can be realized that 50 km distance detection of centimeter space debris with exceeding 90%detection probability, through the filtering of environment noise and selecting of space-based platform parameter. Based on above discussion, it can provide solid basis for the future modeling and simulation research of space based laser centimeter orbital debris detection and removal.
2016, 45(S2): 48-55.
doi: 10.3788/IRLA201645.S229004
The way and characteristics of space debris detection was analyzed. Based on the discussion of the requirements of space-based optical detection system, the system's technical specifications were presented. The detection of brightness higher than sixth-magnitude stars target was achieved, the target positioning precision could reach 3.5. Through the analysis, the influence of stray light which produced of the strong light source in the field of view was controlled in the design process, and the performance of the bright and dark objects could be observed simultaneously. Technical specifications of optical system were:82 mm effective focal length; 70 mm pupil diameter; 1010 field of view; under the condition of 450-900 nm wavelength range, 2 600-9 800 K color temperature range, the deviation of energy centre is better than 3m in the field of view of 0.85, the deviation of energy centre between the various temperature color is better than 1m, meanwhile, spot diagram energy concentration is greater than 75% in the 22 pixel and the spot diagram energy concentration is not less than 90% in the 33 pixel. The requirements of dark targets observation can be met by the sun to suppress the angle is greater than 50, and the PST is not higher than 10-8 which are indicated by the simulation and analysis with the design of baffles and camera lens structures.
2016, 45(S2): 56-61.
doi: 10.3788/IRLA201645.S229005
The core of inferring the debris' tumbling rate via point brightness is to acquire the periodical information of the debris' light curves. Cross-residue method was introduced to infer tumbling rate from the light curves while experimental analysis was made to justify its performance. First, theoretical analysis of cross-residue technique was provided with comparison to other rate inferring methods. Then, experimental measurements of a high-fidelity GEO debris model's light curves under 4 tumble attitudes were conducted as well as cross-residue analysis. Finally, the concept of Cross-residue Reciprocal Peak Significance Rate was put forward to analyze the light curve's cross-residue results, and spectral significance rates were calculated to figure out the best detection waveband. Experimental data shows that tumbling period is accurate and the best detection band is 380-490 nm. The current findings present a foundation for designing of future space-based and ground-based debris surveillance system.
2016, 45(S2): 62-70.
doi: 10.3788/IRLA201645.S229006
The orbital covariance information of debris is wildly used in projects such as uncorrelated tracks catalog and spacecraft collision warning to calculate collision probability. Orbital covariance information contains initial orbit error, measurement equipment error and perturbation model error. It's very important to make a prediction for the covariance above. In the paper, covariance analysis was conducted on low earth orbital objects, International Space Station(ISS) and Japanese satellite AJISAI. The covariance prediction was made through UT transform method of Unscent Kalman Filter and linear covariance method based on Jacobian transform. The simulation results shows that for a period of 200 minutes time, through UKF method the covariance prediction accuracy of ISS increases. But for satellite AJISAI covariance predicted by UKF and linear methods are almost the same. And then, the covariance prediction result from the two methods was compared. At last, through Monte-Carlo method the accuracy of the covariance prediction was verified.
2016, 45(S2): 71-76.
doi: 10.3788/IRLA201645.S229007
According to the signal model of space debris, the frequency diversity technology was reconciled in the imaging method. The frequency diversity can suppress the angle glint of debris, and the average signal-to-noise ratio of echo will be improved. Meanwhile, the demand of bandwidth of two-dimensional imaging of high-speed space debris with small size was too wide to realize, then the low-resolution signal was used to the high-resolution imaging, the bandwidth was much smaller than the need of ISAR, and the influence of the equivalent integration angle caused by high-speed was considered, through the estimation of the equivalent rotating speed, the matched-filter was corrected, which can match the need of rotating imaging and accomplish the imaging. Finally, a simulation of trumpet debris was modeled and made by the method projected in this paper. The result indicates that the method can suppress the angle glint of debris during the time of imaging, and the high resolution image is achieved.
2016, 45(S2): 77-83.
doi: 10.3788/IRLA201645.S229008
According to the signal model of LFM radar, the reason of range, Doppler and wave beam migration, and the variety of target RCS during accumulation period in space debirs detection were analysed. Based on research of compensation on striding three dimension, flight path tracking, and frequency diversity, the signal timewidth and bandwidth influencing on radar detecting ability were analysed and simulated, and a conclusion was obtained that this method was applicable for solving target capture and tarcking precision from far to near distance. At last the simulation demonstrates the validity of the algorithm with providing the compensation on Doppler dimension, LS and Kalman in flight path tracking and variety of range for frequency diversity method.
2016, 45(S2): 84-89.
doi: 10.3788/IRLA201645.S221001
The reflectance spectra of two element cascade structure photonic crystal was studied using transfer matrix method. It shows that total reflection bandwidth of single block photonic crystal (single stage) increases with the physical thickness of media layer increasing, and the band gap position also appears blue-shift. The total reflection bandwidth is rapidly broadening towards long wave as the photonic crystals composed of cascade structure, and the more number of cascades is, the faster broadening is. With the increase of incident angle, the total reflection bandwidth of two element cascades structure of photonic crystal quickly spread to the short-wave direction and with slow red-shift. The properties and modulation rules of reflection spectrum of two element cascade structure photonic crystal can be designed for new photonic crystal omnidirectional reflector and provide theoretical basis for optical switch device.
2016, 45(S2): 90-95.
doi: 10.3788/IRLA201645.S221002
The effect of asymmetric on the transmission properties of one-dimensional temary photonic crystal (CmAmBm)n (BmAmCm)n is studied by transfer matrix theory and numerical simulation method. The result shows that when the photonic crystal is a mirror symmetrical structure (CAB)n(BAC)n, the single transmission peak in the band of spectrum becomes fine with increase of cycle number n, but the transmittance and the wavelength position of transmission peak are unchanged. When the symmetry of the photonic crystal is destroyed, the transmittance of single peak is decrease rapidly, but the wavelength position of transmission peak is constant. The transmittance of single peak is decreasing in varying degrees with increase of asymmetry of the thickness of A, B or C medium layer, and the wavelength position of transmission peak is shifting to long wave direction. However, when the asymmetry of the thickness of A, B and C medium layer are increased at the same time, the transmittance of peak is decreasing and the position of peak is fast blue-shift. The effect mechanism of asymmetry on the transmission properties of One-dimensional temary photonic crystal can provide the theoretical guidance for research and design of optical filter, optical switch and total reflection device.
2016, 45(S2): 96-100.
doi: 10.3788/IRLA201645.S221003
Quartz glass wafer has been widely applied in semiconductor and optical industries. With the rapid development of semiconductor and optical technology, the demand for quartz glass wafer rapidly grows. And the requirements for the processing precision of quartz glass wafer are increasingly strict. In order to meet the customer's demand for quality and quantity of quartz glass wafer, and solving the problems of low processing efficiency, low product precision, non-standard testing and non-standard packaging, based on the actual feedbacks from the use of customer, and refer the processing experience and processing methods of silicon wafer and quartz substrate, the processing techniques of quartz glass wafer was studied from the material making, blank making, precision annealing, multitool cutting, shaping processing, precision polishing, product inspection, cleaning and packaging. Quartz glass wafer, which is produced by current production process, can meet the customer's demand for product quality. And the current production process achieves the mass production. These processing techniques have been validated by market, which can guide the practical operation.
2016, 45(S2): 101-105.
doi: 10.3788/IRLA201645.S220001
Low light level night vision goggle has been benefit to pilot for carrying out terrain reconnaissance, making up air flight, and air-to-ground attacking at night. Image intensifier assembly can intensify the low light image projected by object at night to bright one fitted to be observed by human. According to the spectral response of image intensifier, NVIS compatible characteristic and spectrum matching performance of super-second and the third generation low light level image intensifier assembly was analyzed. Operational performance of different night vision goggles was derived by calculating formula. It is shown that the third generation low light level image intensifier assembly has better NVIS compatible characteristic than super-second generation by means of good spectrum matching performance and high quantum efficiency, which is benefit to reconstruct the NVIS compatible cockpit lighting. Meanwhile, because of higher signal to noise ratio, night vision system equipped the third generation low light level image intensifier assembly can discover farther object than the second generation.
2016, 45(S2): 106-109.
doi: 10.3788/IRLA201645.S220002
The high performance phosphor screen can effectively enhance the performance of low light level image intensifiers. The performance of phosphor screen mainly depends on the nature of the powder layer. The powder layer is essentially formed by the accumulation of phosphor grains, and therefore the related character research of the powder layer based on powder stacking theory is helpful to guide the actual production process to obtain higher quality powder layer, thereby enhancing the performance of the screen. Therefore, a theoretical analysis of the powder layer density based on the classic powder stacking theory was made, and combined with the actual production, some further related studies for the best powder layer thickness were obtained, taking a certain type of phosphor for example. The result shows that the powder layer first should be possible to achieve the optimum thickness, and then make the density to the maximum, so can obtain the better powder layer, hence, the performance of phosphor screen will get better.
2016, 45(S2): 110-114.
doi: 10.3788/IRLA201645.S218001
Impulse coupling effect of short pulsed laser ablation the target has great application in the fields of laser orbital debris removal. High precision impulse measurement is the necessary method in studying the impulse coupling effect. Based on the impulse measurement background in laser orbital debris removal, the torsion pendulum method was analyzed, the response equation was obtained in the situation of pulse micro thrust interaction. All these will provide the research basis for the design of measurement system and experimental research. According to the actual circumstance, that was the space debris ablated by a certain frequency laser pulse, the simulation analysis of response characteristics of torsion pendulum was conducted by multi-pulse micro-thrust. The conclusions are as follows:the system response curve is a sine curve and the vibration amplitude attention depends on the damping ratio; the impulse amplitude depends on the pulse force; when the force interaction time is less than the 1/8 of the torsion period, the force can be considered as an instant impulse effect; in this situation, the response effect is almost the same when the total torque is the same, although the number of pulse force is different. The system error is concerned with damping ratio and the ratio of the force time and the torsion period.
2016, 45(S2): 115-119.
doi: 10.3788/IRLA201645.S218002
In order to solve the problem of simultaneous, object imaging and contrast demonstrating in near ultraviolet, visible light and near-infrared, the design thinking of constructing an imaging contrast demonstrating system was put forward. Three parts of image collectors, signal processing platform and image output projections was designed and constructed. A tri-band simultaneous and actual output demonstrating platform was established. From the spectral response verification of platform, and the imaging contrast of the human-made such as paint, color chip, fabrics patterns and artificial plants, the purpose of tri-band simultaneous and contrast imaging was realized.
2016, 45(S2): 120-125.
doi: 10.3788/IRLA201645.S223001
A novel non-negative sparse representation (NSR) model was proposed for hyperspectral anomaly detection. The key idea was that a background pixel can be approximately represented as a sparse linear combination of its surrounding neighbors, while an anomalous pixel cannot. The non-negativity and one-to-one constraints on the sparse vector were imposed for physical meaning and better discrimination power of the algorithm. In order to exclude the potential anomalous pixels presented in the background dictionary, the atoms which were similar to the center pixel was pruned. Then the NSR model was solved by non-negative orthogonal matching pursuit (NOMP) algorithm, and the reconstruction errors were directly used for determining the anomalies. Finally, experimental results on real hyperspectral data set demonstrate the effectiveness of the proposed algorithms by comparing it with state-of-the-art algorithms.
2016, 45(S2): 126-131.
doi: 10.3788/IRLA201645.S223002
The traditional registration method is based on the search area registration and it is carried out at control points of the image coordinates of discrete points, but this method will limit the positioning accuracy of the registration control point. Aiming at this problem, a high spectral registration method which is based on Gaussian fitting was preseuted. Similar to the traditional registration method based on region, this method also used the gray information of images to build the similarity measure between two images and searched the point at which the similarity measure can reach its maximum or minimum to be the registration control points. Different with the traditional methods, it did not go straight for the extreme point and used it as the registration control point during the process of search, instead, the similarity-matrix was produced at first during the process of search and coefficients of Gaussian fitting function could be obtained from the value near the extreme points, the extreme points of Gaussian fitting function were used as the registration control points to complete the registration. The multiple sets of experimental results of hyperion high spectral registration all show that the method presented in the paper is more accurate than the traditional methods, and the registration accuracy reaches sub-pixel successfully, the method can meet the follow-up demands such as fusion, change detection and so on.
2016, 45(S2): 132-139.
doi: 10.3788/IRLA201645.S223003
To solve the problem that traditional hyperspectral target detection is based on either airborne image or spaceborne image, and doesn't utilize the advantage of aerial and space imaging comprehensively, a target detection method for airborne and spaceborne image fusion, which combined 3D GMRF with D-S evidence theory, was proposed in this paper. The 3D GMRF detection results from airborne image and spaceborne image were fused by D-S evidence theory in decision level. The experimental results show that the proposed target detection method complements the advantage of aerial hyperspectral image and space hyperspectral image, and enhances accuracy on target detection. This technology is new target detection method by fusing the aerial and space hyperspectral image.
2016, 45(S2): 140-144.
doi: 10.3788/IRLA201645.S226001
In this paper, the method for optical remote sensing image in the quantum space was present. The model of quantization remote sensing image was formulated, based on the theory of quantum mechanics. The image was firstly transformed into different scale information by shift invariant wavelet. Secondly, the image was transformed to the quantum superposition state form. The further step leaded to the information being decomposed into different quantum bit(Qubit) planes. And the information was optimized by norm on every Qubit plane, following the quantum computational theorem. Finally, the remote sensing image was reassembled in the procedure of reconstruction. The experimental result shows that evaluation index of the restored image is improved, which means that processed image has better quality than conventional filtering methods.
