2008 Vol. 1, No. 1
2008, 1(1): 1-12.
Abstract
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Abstract:
High resolution visible earth observation on the Geostationary Earth Orbit（GEO） has a series of unique advantages over that in the other orbits. However, long range and high resolution visible observation requests a large primary mirror more than 20 m in the diameter. The traditional Space Telescope (ST) with such a large primeny mirror can not be launched to GEO, for its total mass is more than 1 000 t. An unsupported membrane ST and a large diameter diffraction ST can significantly reduce mirror surface density and lower down the total mass of the ST, which offers an excellent technologic approach to earth observation. Moreover, both the launching by module and the assembly in an orbit provide the technological means to transport these kinds of observation systems from ground to GEO. Fourier telescope based on the theory of transform imaging changes the acquirement for high resolution from increasing the receiving diameter into increasing the illumination interval, and from detecting the object image directly into receiving the echo energy and reconstructing Fourier components. It breaks through the fatal bottleneck of the long range and high resolution observation. Recently, a near perfect lens has been developed to provide the possibility for breakthrough of diffraction limit, so that a new science field will be set up for super resolution observation. The perfect lens makes of negative refractive index materials(left handed materials) and the negative refractive index materials come from both of the photonic crystals and the photonic devices based on Surface Plasmon Polariton (SPP).
High resolution visible earth observation on the Geostationary Earth Orbit（GEO） has a series of unique advantages over that in the other orbits. However, long range and high resolution visible observation requests a large primary mirror more than 20 m in the diameter. The traditional Space Telescope (ST) with such a large primeny mirror can not be launched to GEO, for its total mass is more than 1 000 t. An unsupported membrane ST and a large diameter diffraction ST can significantly reduce mirror surface density and lower down the total mass of the ST, which offers an excellent technologic approach to earth observation. Moreover, both the launching by module and the assembly in an orbit provide the technological means to transport these kinds of observation systems from ground to GEO. Fourier telescope based on the theory of transform imaging changes the acquirement for high resolution from increasing the receiving diameter into increasing the illumination interval, and from detecting the object image directly into receiving the echo energy and reconstructing Fourier components. It breaks through the fatal bottleneck of the long range and high resolution observation. Recently, a near perfect lens has been developed to provide the possibility for breakthrough of diffraction limit, so that a new science field will be set up for super resolution observation. The perfect lens makes of negative refractive index materials(left handed materials) and the negative refractive index materials come from both of the photonic crystals and the photonic devices based on Surface Plasmon Polariton (SPP).
2008, 1(1): 13-24.
Abstract:
Coming into 21 century, a number of developed countries and relational government organizations in the world, such as National Aeronautics and Space Administration(NASA) in America, European Space Agency (ESA), and some organization in Russia, have established a series of strategic projects about space science development. These projects point out some problems to be solved in space science and provide the way forward for space technology, also it indicate that development of space science is dependent on advance optical and radio telescope as well as their instruments. Therefore, this paper introduces some large astronomical telescopes used in international space science studies at the beginning of 21 century, and describes several optical systems in large aperture space telescopes mainly. Finally, the wave front sensing technique which is the key technology in the development of large astronomical telescopes is discussed.
Coming into 21 century, a number of developed countries and relational government organizations in the world, such as National Aeronautics and Space Administration(NASA) in America, European Space Agency (ESA), and some organization in Russia, have established a series of strategic projects about space science development. These projects point out some problems to be solved in space science and provide the way forward for space technology, also it indicate that development of space science is dependent on advance optical and radio telescope as well as their instruments. Therefore, this paper introduces some large astronomical telescopes used in international space science studies at the beginning of 21 century, and describes several optical systems in large aperture space telescopes mainly. Finally, the wave front sensing technique which is the key technology in the development of large astronomical telescopes is discussed.
2008, 1(1): 25-35.
Abstract:
Lithographic exposure is the key process in the manufacture of integrated circuit, and the performance of exposure system decides the level of microelectronic manufacture technology. In this paper, the present status and progress in 193 nm exposure system are described. The resolution enhancement technologies widely used in 193 nm lithography, such as offaxis illumination, phase shifting mask and optical proximity correction, are also introduced. By showing the composition and key technologies of the exposure system, the challenges in development of lithography instrument are discussed.
Lithographic exposure is the key process in the manufacture of integrated circuit, and the performance of exposure system decides the level of microelectronic manufacture technology. In this paper, the present status and progress in 193 nm exposure system are described. The resolution enhancement technologies widely used in 193 nm lithography, such as offaxis illumination, phase shifting mask and optical proximity correction, are also introduced. By showing the composition and key technologies of the exposure system, the challenges in development of lithography instrument are discussed.
2008, 1(1): 49-56.
Abstract:
The development history and research situation of Photovoltaic(PV) concentrator system are briefly reported in this paper. The concentrators and solar cells for PV system are classified in detail, then their characteristicsand technological parameters are introduced. Several solar tracking systems developed by foreign countries are described, which can improve the conversion efficiency and can reduce produce cost for PV system. Moreover, two kinds of applied tendencies about PV concentrator system are discussed, they are high magnification concentrator+tracking system and low magnification and large angle concentrator+beam splitter+multisection batteries. Finally, main problems on the commercialization of PV concentrator system are presented.
The development history and research situation of Photovoltaic(PV) concentrator system are briefly reported in this paper. The concentrators and solar cells for PV system are classified in detail, then their characteristicsand technological parameters are introduced. Several solar tracking systems developed by foreign countries are described, which can improve the conversion efficiency and can reduce produce cost for PV system. Moreover, two kinds of applied tendencies about PV concentrator system are discussed, they are high magnification concentrator+tracking system and low magnification and large angle concentrator+beam splitter+multisection batteries. Finally, main problems on the commercialization of PV concentrator system are presented.
2008, 1(1): 57-61.
Abstract:
As one of the important technical specifications of diffraction grating, diffraction wave front aberration directly affects the grating resolution. Recording the interference fringe produced from two coherent light beams by use of photoresist is a key process in manufacturing a holographic grating. According to the influence of defocus on collimating light parallelism of reflecting spherical collimating mirror, this paper analyzes the influence of collimating light parallelism on the wave front of holographic grating to improve setting accuracy, minimize defocus of exposure system in holographic grating, and to reduce diffraction wave front aberration of grating. The results of theoretic analysis and numerical simulation show that diffraction wave front aberration of grating is directly determined by the adjusting error of collimating mirror. In addition, by taking three kinds of gratings with different ruling densities for examples, the allowable range of adjusting error of collimating mirror is obtained.
As one of the important technical specifications of diffraction grating, diffraction wave front aberration directly affects the grating resolution. Recording the interference fringe produced from two coherent light beams by use of photoresist is a key process in manufacturing a holographic grating. According to the influence of defocus on collimating light parallelism of reflecting spherical collimating mirror, this paper analyzes the influence of collimating light parallelism on the wave front of holographic grating to improve setting accuracy, minimize defocus of exposure system in holographic grating, and to reduce diffraction wave front aberration of grating. The results of theoretic analysis and numerical simulation show that diffraction wave front aberration of grating is directly determined by the adjusting error of collimating mirror. In addition, by taking three kinds of gratings with different ruling densities for examples, the allowable range of adjusting error of collimating mirror is obtained.
2008, 1(1): 62-65.
Abstract:
A new method based on Radial Basis Function(RBF) neural network was proposed to correct the system error of a optical encoder. The modeling method of RBF was introduced in detail and the theoretical basis for adjusting the parameters of the model was given. A new model for error correction was set up by taking the test values of the high precision instrument as outputs and the angle values of sample points as inputs. The testing results show that the precision of the encoder by this method has increased by 3 times as compared with that of traditional method and the precision of measuring system is improved greatly by using the RBF model as error compensation.
A new method based on Radial Basis Function(RBF) neural network was proposed to correct the system error of a optical encoder. The modeling method of RBF was introduced in detail and the theoretical basis for adjusting the parameters of the model was given. A new model for error correction was set up by taking the test values of the high precision instrument as outputs and the angle values of sample points as inputs. The testing results show that the precision of the encoder by this method has increased by 3 times as compared with that of traditional method and the precision of measuring system is improved greatly by using the RBF model as error compensation.
2008, 1(1): 66-69.
Abstract:
To reproduce the supreme diameter and high precision grating, the mechanical properties of bearing board in exposure equipment for reproducing grating was analyzed. By summing up the mechanical analysis on bearing board into a flexibility problem, the formula of the relationship between flexibility and thickness was deduced by theoretical calculation. On the basis of the formula, an exposure equipment with bearing board in thickness of 40 mm and diameter of 1 000 mm was used to reproduce a high precision and large diameter thin grating successfully, experimental results show that the biggest diameter error and uniformity error of the grating is 047″ and 8%, respectively, which can meet the requirement for angle measurement system.
To reproduce the supreme diameter and high precision grating, the mechanical properties of bearing board in exposure equipment for reproducing grating was analyzed. By summing up the mechanical analysis on bearing board into a flexibility problem, the formula of the relationship between flexibility and thickness was deduced by theoretical calculation. On the basis of the formula, an exposure equipment with bearing board in thickness of 40 mm and diameter of 1 000 mm was used to reproduce a high precision and large diameter thin grating successfully, experimental results show that the biggest diameter error and uniformity error of the grating is 047″ and 8%, respectively, which can meet the requirement for angle measurement system.
2008, 1(1): 70-74.
Abstract:
Traditional spatial concealment effect is described by Weber law. However， it only considers photopic vision， and can not fit to weaker or stronger light intensity. In order to depict spatial concealment effect more effectively， a novel fitting formula was proposed only by signal processing method. Several different models is used to fit the data in Konig and Brodhun in experiments， and the fitted results demonstrate that the root mean square error of the proposed model is only 0010 2， which is less than those of traditional Weber law， superior form of Weber law， Guilford model， and Chen model. It can be concluded that proposed model can fit to human eyes in more expansive range of light intensity， and can be applied to engineering practice more widely.
Traditional spatial concealment effect is described by Weber law. However， it only considers photopic vision， and can not fit to weaker or stronger light intensity. In order to depict spatial concealment effect more effectively， a novel fitting formula was proposed only by signal processing method. Several different models is used to fit the data in Konig and Brodhun in experiments， and the fitted results demonstrate that the root mean square error of the proposed model is only 0010 2， which is less than those of traditional Weber law， superior form of Weber law， Guilford model， and Chen model. It can be concluded that proposed model can fit to human eyes in more expansive range of light intensity， and can be applied to engineering practice more widely.
2008, 1(1): 75-79.
Abstract:
To solve the problem of online measuring micro-target parts in assembling process, a micro-vision measuring system was designed and developed in this paper. The composition of miro-vision system, implementation of micro image capturing, image preprocessing, and character measurement were described. In the preprocessing, a new refiltering and denoising algorithm and a character measuring algorithm were presented for microtarget parts. Then, the system was used to measure the microtarget parts such as Al sidestep sample, and hohlraums. Experimental results indicate that proposed system can measure the geometric characters and sample positions in real time, high speed and high precision for target parts. When measuring field of view is 3 mm, the geometric measuring precision and angle precision are less than 3 μm and 01°, respectively, which shows proposed system is suitable for the assembling process of microtarget part.
To solve the problem of online measuring micro-target parts in assembling process, a micro-vision measuring system was designed and developed in this paper. The composition of miro-vision system, implementation of micro image capturing, image preprocessing, and character measurement were described. In the preprocessing, a new refiltering and denoising algorithm and a character measuring algorithm were presented for microtarget parts. Then, the system was used to measure the microtarget parts such as Al sidestep sample, and hohlraums. Experimental results indicate that proposed system can measure the geometric characters and sample positions in real time, high speed and high precision for target parts. When measuring field of view is 3 mm, the geometric measuring precision and angle precision are less than 3 μm and 01°, respectively, which shows proposed system is suitable for the assembling process of microtarget part.
2008, 1(1): 80-84.
Abstract:
MgxZn1-xO is a promising material for developing solarblind ultraviolet(UV) photodetectors. However, the control of the MgZnO quality and the phase separation with increase of Mg in MgxZn1-xOO alloy is still a difficult problem. Up to now, no reports that the cutoff wavelength is at 273 nm have been found for the photodetectors based on MgZnO films. In this paper, cubic MgxZn1-xOO thin films are grown on quartz and sapphire substrates by Radio Frequency(RF) magnetron sputtering and Metal Organic Chemical Vapour Deposition(MOCVD). The MetalSemiconductorMetal(MSM) structured MgZnO photodetectors are fabricated based on the films. Results from spectral analysis shows that the photodetector exhibits a peak response wavelength at 225 nm with a cutoff wavelength of 230 nm, and the cubic phase MgZnO alloy with 255 nm absorption edge is finished by LPMOCVD and the MSM devices exhibit the peak energy at 250 nm with cutoff wavelength of 273 nm, which lies in the solarblind spectrum range(220~280 nm).
MgxZn1-xO is a promising material for developing solarblind ultraviolet(UV) photodetectors. However, the control of the MgZnO quality and the phase separation with increase of Mg in MgxZn1-xOO alloy is still a difficult problem. Up to now, no reports that the cutoff wavelength is at 273 nm have been found for the photodetectors based on MgZnO films. In this paper, cubic MgxZn1-xOO thin films are grown on quartz and sapphire substrates by Radio Frequency(RF) magnetron sputtering and Metal Organic Chemical Vapour Deposition(MOCVD). The MetalSemiconductorMetal(MSM) structured MgZnO photodetectors are fabricated based on the films. Results from spectral analysis shows that the photodetector exhibits a peak response wavelength at 225 nm with a cutoff wavelength of 230 nm, and the cubic phase MgZnO alloy with 255 nm absorption edge is finished by LPMOCVD and the MSM devices exhibit the peak energy at 250 nm with cutoff wavelength of 273 nm, which lies in the solarblind spectrum range(220~280 nm).
2008, 1(1): 85-91.
Abstract:
A novel lipophilic dirhenium complex fac-[{Re(CO)3(d19phen)}2(4,4′bipyridylacetylene)](OTf)2，(denoted as DRe(I))(d19phen=4,7dinonadecyl1,10phenanthroline and OTf=trifluoromethanesulfonate) was doped homogeneously in polystyrene(PS) and polymethyl methacrylate(PMMA) fibers by electrospinning method and the oxygen quenching fluorescence behavior was systematically investigated. The linear SternVolmer model, the Demas and Lehrer models were used to fit the obtained SternVolmer curves of the composite fibers. An oxygen sensor based on the DRe(I) composite fibers shows short response time, good reproducible signals, and linear SternVolmer plots attributed to the existence of the ligand containing long alkyl chain groups that makes DRe(I) become soluble in the polymers.
A novel lipophilic dirhenium complex fac-[{Re(CO)3(d19phen)}2(4,4′bipyridylacetylene)](OTf)2，(denoted as DRe(I))(d19phen=4,7dinonadecyl1,10phenanthroline and OTf=trifluoromethanesulfonate) was doped homogeneously in polystyrene(PS) and polymethyl methacrylate(PMMA) fibers by electrospinning method and the oxygen quenching fluorescence behavior was systematically investigated. The linear SternVolmer model, the Demas and Lehrer models were used to fit the obtained SternVolmer curves of the composite fibers. An oxygen sensor based on the DRe(I) composite fibers shows short response time, good reproducible signals, and linear SternVolmer plots attributed to the existence of the ligand containing long alkyl chain groups that makes DRe(I) become soluble in the polymers.
Development of measuring instrument of optical axis parallelism for strong laser and infrared sensor
2008, 1(1): 100-104.
Abstract:
A measuring instrument for optical axis parallelism was developed. By transfering laser region of 106 μm to infrared region of 3~5 μm and 8~12 μm with a heat target technique, the parallel error of optical axis between strong laser emitter and infrared sensor of a photoelectric tracking equipment was measured successfully. The structure of measuring instrument was designed as absolutely symmetrical and toy brick assembly shapes to maintain the measuring precision under the abominable conditions. Then, an ingenious electromagnetic switch was used to control and convert target surface for long distance and new assembly techniques and several check steps were taken to improve the measuring precision. Finally various environment tests were carried out to validate the reliability of measuring instrument. Experiment results show that the accuracy of the measuring instrument can reach up to 10″, also can maintain its accuracy ≤10″ under temperature of -30 ℃~+60 ℃.
A measuring instrument for optical axis parallelism was developed. By transfering laser region of 106 μm to infrared region of 3~5 μm and 8~12 μm with a heat target technique, the parallel error of optical axis between strong laser emitter and infrared sensor of a photoelectric tracking equipment was measured successfully. The structure of measuring instrument was designed as absolutely symmetrical and toy brick assembly shapes to maintain the measuring precision under the abominable conditions. Then, an ingenious electromagnetic switch was used to control and convert target surface for long distance and new assembly techniques and several check steps were taken to improve the measuring precision. Finally various environment tests were carried out to validate the reliability of measuring instrument. Experiment results show that the accuracy of the measuring instrument can reach up to 10″, also can maintain its accuracy ≤10″ under temperature of -30 ℃~+60 ℃.
2008, 1(1): 105-111.
Abstract:
On the basis of the rate equation and the optical transmission equation for a double clad fiber laser, a mathematical model was established to calculate the output power for the optical fiber laser. Then, the distribution of output power along optical fiber and distributions of output power and pump power in different fiber lengths were simulated numerically for a neodymium doped fiber laser. By taking a 808 nm semiconductor laser as pumping source. By taking a neodymium doped double clad fiber as gain medium and KTP crystal as a multiplier, the efficiency of doubling frequency and phase angle of the laser were calculated and simulated. Finally, the frequency doubling of fiber lasers was simulated. Experimental results show that the fiber laser can achieve visible light output in high efficiency.
On the basis of the rate equation and the optical transmission equation for a double clad fiber laser, a mathematical model was established to calculate the output power for the optical fiber laser. Then, the distribution of output power along optical fiber and distributions of output power and pump power in different fiber lengths were simulated numerically for a neodymium doped fiber laser. By taking a 808 nm semiconductor laser as pumping source. By taking a neodymium doped double clad fiber as gain medium and KTP crystal as a multiplier, the efficiency of doubling frequency and phase angle of the laser were calculated and simulated. Finally, the frequency doubling of fiber lasers was simulated. Experimental results show that the fiber laser can achieve visible light output in high efficiency.
