The fundamental measurement of space gravitational wave detection is to monitor the relative motion between pairs of freely falling test masses using heterodyne laser interferometry to a precision of 10 pm. The masses...The fundamental measurement of space gravitational wave detection is to monitor the relative motion between pairs of freely falling test masses using heterodyne laser interferometry to a precision of 10 pm. The masses under test are millions of kilometers apart. The inter-spacecraft laser interferometry telescope deliver laser efficiently from one spacecraft to another. It is an important component of the gravitational wave detection observatory. It needs to meet the requirements of large compression ratio, high image quality and extraordinary stray light suppression ability. Based on the primary aberration theory, the method of the large compression ratio off-axis four-mirror optical system design is explored. After optimization, the system has an entrance pupil of 200 mm, compression ratio of 40 times, scientific field of view (FOV) of ±8 μrad. To facilitate suppressing the stray light and delivering the laser beam to the back-end scientific interferometers, the intermediate images and the real exit pupils are spatially available. Over the full FOV, the maximum root mean square (RMS) wavefront error is less than 0.007λ, PV value is less than 0.03λ (λ = 1064 nm). The image quality is approached to the diffraction-limit. The TTL noise caused by the wavefront error of the telescope is analyzed. The TTL noise in the image space of 300 μrad range is less than 1 × 10-10 m whose slope is lower than 0.6 μm/rad, which is under the noise budget of the laser interferometer space antenna (LISA), satisfying the requirements of space gravitational wave detection.展开更多
In this paper, we present a comparison of different light-emitting diodes （LEDs） as the light source for long path differential optical absorption spectroscopy （LP-DOAS） atmospheric trace gas measurements. In our ...In this paper, we present a comparison of different light-emitting diodes （LEDs） as the light source for long path differential optical absorption spectroscopy （LP-DOAS） atmospheric trace gas measurements. In our study, we use a fiberoptic design, where high power LEDs used as the light source are coupled into the telescope using a Y shape fiber bundle. Two blue and one ultraviolet （UV） LEDs with different emission wavelength ranges are tested for NO2 and SO2 measurements. The detailed description of the instrumental setup, the NO2 and SO2 retrieval procedure, the error analysis, and the preliminary results from the measurements carried out in Science Island, Hefei, Anhui, China are presented. Our first measurement results show that atmospheric NO2 and SO2 have strong temporal variations in that area and that the measurement accuracy is strongly dependent on the visibility conditions. The measured NO2 and SO2 data are compared to the Ozone Monitoring Instrument （OMI） satellite observations. The results show that the OMI NO2 product underestimates the ground level NO2 by 45%, while the OMI SO2 data are highly influenced by clouds and aerosols, which can lead to large biases in the ground level concentrations. During the experiment, the mixing ratios of the atmospheric NO2 and SO2 vary from 8 ppbv to 36 ppbv and from 3 ppbv to 18 ppbv, respectively.展开更多
The exoplanet search is one of the most exciting research fields in astrophysics. The Antarctic Bright Star Survey Telescope(BSST), capable of continuous exoplanet observation on polar nights, is a Ritchey–Chretien t...The exoplanet search is one of the most exciting research fields in astrophysics. The Antarctic Bright Star Survey Telescope(BSST), capable of continuous exoplanet observation on polar nights, is a Ritchey–Chretien telescope with a three-lens field corrector, and has a 300 mm aperture, 2.76 focal ratio, and a wavelength coverage ranging from 0.36 to 1.014 μm. Equipped with a 4 k × 4 k and 12 μm∕pixel CCD camera, the BSST can gain a field of view of 4.8°. This Letter presents the optical design, tolerance analysis, and the alignment plan for the BSST, and the test observation results.展开更多
This paper introduces configuration of the main optical system of China’s 2.16-m telescope and the results of its optical design. There are three foci in this telescope: the Cassegrain, the coude and the prime foci. ...This paper introduces configuration of the main optical system of China’s 2.16-m telescope and the results of its optical design. There are three foci in this telescope: the Cassegrain, the coude and the prime foci. Ritchey-Chretien (R-C) system is used as the Cassegrain system. The 2-lens and 3-lens correctors are prepared for the Cassegrain and the prime foci respectively. The most significant characteristic of this optical system is that the coude and Cassegrain systems share one secondary mirror. A relay mirror is added to the coude system. When the two systems exchange, the secondary mirror moves slightly, and the coude system obtained is free from both spherical aberration and coma simultaneously. Some other coude configurations and a special configuration for setting the focal reducer are also introduced in this paper.展开更多
离轴反射系统设计的关键环节是确定适用初始结构并进行优化,一般从同轴结构或者专利库中寻找相似的结构开始优化,这往往需要耗费大量的时间。以Seidel像差理论为依据,研究了一种获取离轴四反系统初始结构的设计方法。在设计之初引入视...离轴反射系统设计的关键环节是确定适用初始结构并进行优化,一般从同轴结构或者专利库中寻找相似的结构开始优化,这往往需要耗费大量的时间。以Seidel像差理论为依据,研究了一种获取离轴四反系统初始结构的设计方法。在设计之初引入视场偏置,通过追迹近轴光线给出五种单色像差的初级Seidel像差表示。以Seidel像差绝对值最小化作为目标函数,同时加入对光学和系统结构上的限制条件构建含有约束条件的单目标非线性优化模型,并通过粒子群优化算法进行求解。在此基础上,通过MATLAB调用CODE V API接口,判断此视场偏置情况下是否满足无遮拦的条件,并从中挑选出满足条件的初始结构。设计了一款焦距为1200 mm,视场1.2°×20°,F数为6的离轴四反光学系统,系统结构布局紧凑,成像质量良好,各项指标均满足设计要求。展开更多
文摘The fundamental measurement of space gravitational wave detection is to monitor the relative motion between pairs of freely falling test masses using heterodyne laser interferometry to a precision of 10 pm. The masses under test are millions of kilometers apart. The inter-spacecraft laser interferometry telescope deliver laser efficiently from one spacecraft to another. It is an important component of the gravitational wave detection observatory. It needs to meet the requirements of large compression ratio, high image quality and extraordinary stray light suppression ability. Based on the primary aberration theory, the method of the large compression ratio off-axis four-mirror optical system design is explored. After optimization, the system has an entrance pupil of 200 mm, compression ratio of 40 times, scientific field of view (FOV) of ±8 μrad. To facilitate suppressing the stray light and delivering the laser beam to the back-end scientific interferometers, the intermediate images and the real exit pupils are spatially available. Over the full FOV, the maximum root mean square (RMS) wavefront error is less than 0.007λ, PV value is less than 0.03λ (λ = 1064 nm). The image quality is approached to the diffraction-limit. The TTL noise caused by the wavefront error of the telescope is analyzed. The TTL noise in the image space of 300 μrad range is less than 1 × 10-10 m whose slope is lower than 0.6 μm/rad, which is under the noise budget of the laser interferometer space antenna (LISA), satisfying the requirements of space gravitational wave detection.
基金Project supported by the National High-Technology Research and Development Program of China (Grant No. 2009AA063006)the National Natural Science Foundation of China (Grant No. 60808034)
文摘In this paper, we present a comparison of different light-emitting diodes （LEDs） as the light source for long path differential optical absorption spectroscopy （LP-DOAS） atmospheric trace gas measurements. In our study, we use a fiberoptic design, where high power LEDs used as the light source are coupled into the telescope using a Y shape fiber bundle. Two blue and one ultraviolet （UV） LEDs with different emission wavelength ranges are tested for NO2 and SO2 measurements. The detailed description of the instrumental setup, the NO2 and SO2 retrieval procedure, the error analysis, and the preliminary results from the measurements carried out in Science Island, Hefei, Anhui, China are presented. Our first measurement results show that atmospheric NO2 and SO2 have strong temporal variations in that area and that the measurement accuracy is strongly dependent on the visibility conditions. The measured NO2 and SO2 data are compared to the Ozone Monitoring Instrument （OMI） satellite observations. The results show that the OMI NO2 product underestimates the ground level NO2 by 45%, while the OMI SO2 data are highly influenced by clouds and aerosols, which can lead to large biases in the ground level concentrations. During the experiment, the mixing ratios of the atmospheric NO2 and SO2 vary from 8 ppbv to 36 ppbv and from 3 ppbv to 18 ppbv, respectively.
基金Polar Research Institute of Chinathe University of Science and Technology of China for their supportsupported by the SOC program (CHINARE2012-02-03)
文摘The exoplanet search is one of the most exciting research fields in astrophysics. The Antarctic Bright Star Survey Telescope(BSST), capable of continuous exoplanet observation on polar nights, is a Ritchey–Chretien telescope with a three-lens field corrector, and has a 300 mm aperture, 2.76 focal ratio, and a wavelength coverage ranging from 0.36 to 1.014 μm. Equipped with a 4 k × 4 k and 12 μm∕pixel CCD camera, the BSST can gain a field of view of 4.8°. This Letter presents the optical design, tolerance analysis, and the alignment plan for the BSST, and the test observation results.
文摘This paper introduces configuration of the main optical system of China’s 2.16-m telescope and the results of its optical design. There are three foci in this telescope: the Cassegrain, the coude and the prime foci. Ritchey-Chretien (R-C) system is used as the Cassegrain system. The 2-lens and 3-lens correctors are prepared for the Cassegrain and the prime foci respectively. The most significant characteristic of this optical system is that the coude and Cassegrain systems share one secondary mirror. A relay mirror is added to the coude system. When the two systems exchange, the secondary mirror moves slightly, and the coude system obtained is free from both spherical aberration and coma simultaneously. Some other coude configurations and a special configuration for setting the focal reducer are also introduced in this paper.
文摘离轴反射系统设计的关键环节是确定适用初始结构并进行优化,一般从同轴结构或者专利库中寻找相似的结构开始优化,这往往需要耗费大量的时间。以Seidel像差理论为依据,研究了一种获取离轴四反系统初始结构的设计方法。在设计之初引入视场偏置,通过追迹近轴光线给出五种单色像差的初级Seidel像差表示。以Seidel像差绝对值最小化作为目标函数,同时加入对光学和系统结构上的限制条件构建含有约束条件的单目标非线性优化模型,并通过粒子群优化算法进行求解。在此基础上,通过MATLAB调用CODE V API接口,判断此视场偏置情况下是否满足无遮拦的条件,并从中挑选出满足条件的初始结构。设计了一款焦距为1200 mm,视场1.2°×20°,F数为6的离轴四反光学系统,系统结构布局紧凑,成像质量良好,各项指标均满足设计要求。
