基于Fery棱镜分光的太阳光谱仪研究

	基于Fery棱镜分光的太阳光谱仪研究
	张浩
学位类型	博士
导师	方伟
	2014-07
学位授予单位	中国科学院大学
学位专业	光学工程
摘要	监测太阳辐射变化对太阳物理研究具有重要意义，并可为地球气候变化、地球空间天气预报等应用研究提供必要的基础科学数据。太阳辐射测量包括太阳总辐照度（TSI）测量和太阳光谱辐照度（SSI）测量两个方面。国际上已对地球大气层上界（TOA）TSI进行了大量高精度、不间断和重叠测量；但SSI测量则缺少足够的精度和时间连续性，尤其是波段覆盖很不完整。鉴于此，对以航天应用为背景的宽光谱棱镜型太阳光谱仪（Solar Prism Spectrometer, SPS）进行了深入研究，依次进行了棱镜分光光路的光学系统设计和性能仿真、新型高精度波长反馈机构的光电系统设计、低噪声光谱信号检测方法研究以及SPS原理样机的波长/辐射定标方法研究等。首先，依据Féry棱镜原理，设计了SPS的扫描式主分光光路系统，工作波长范围0.25~2.50 μm；棱镜在±2.5°转角内均平谱面成像，并由4个出射狭缝及对应的不同响应波段的光电二极管探测器同时扫描接收。基于Huygens点扩散函数（PSF）和线性系统理论提出了光谱响应函数（SRF）的计算机仿真方法，依据SRF仿真数据，计算了各出射狭缝的光谱带宽为1~41 nm，并推导了各出射狭缝接收的中心波长与棱镜转角的关系。为实现棱镜转角的高精度反馈，设计了基于凹面反射镜和线阵CCD的参考光路系统。其次，设计了由嵌入式控制系统和PC机主控软件组成的SPS的电子学控制系统。高精度光电信号检测和精密波长扫描分别是SPS辐射度精度和波长精度的保证；设计了光电二极管低噪声前端放大电路，通过实验测得VNIR1和VNIR2两光谱通道的信噪比均大于1000；通过高性能步进电机驱动系统和高速比减速器机构实现棱镜0.8″的步进分辨率，使用参考光路CCD像斑的重心定位法实现角度反馈不确定度达到0.09″。设计了PC机主控软件的调试模式、测量模式和定标模式，用来实现对SPS的远程控制。最后，使用汞灯和高分辨率光栅单色仪对SPS原理样机进行了波长定标实验，通过多项式拟合方法建立了VNIR1和VNIR2两光谱通道的输出波长与参考光路CCD像斑位置间的函数关系，波长定标不确定度分别优于0.34nm和0.88nm。分析了波长扫描法（直接法）和棱镜扫描法（间接法）测量SRF的等效性，并使用632.8nm激光器光源进行了SRF的棱镜扫描法测量实验，获得的光谱带宽与仿真结果相差7%以内。使用1000W标准灯对SPS进行了辐照度定标实验，获取了辐射定标系数，定标不确定度为~3.17%；同时分析了辐射测量不确定度，达到~3.18%。
其他摘要	Measurements of solar radiation and its variation are not only important for solar physics research, but also necessary for studies on the Earth's climate changes, space weather forecast and other application areas. Total Solar Irradiance (TSI) and Solar Spectral Irradiance (SSI) are the two aspects of solar radiation measurements. Precise, continuous and overlapped TSI measurements at Top of the Atmosphere (TOA) have been taken out internationally, whereas the SSI measurements are still lack of sufficient accuracy and temporal continuity, especially difficult to cover the whole spectral range. Therefore, a spaceborne Solar Prism Spectrometer(SPS) with wide spectral coverage is suggested. The tasks of optimization and simulation of prism-dispersion optical system, design of precision wavelength scan and feedback system, low-noise detection of weak spectral signals, wavelength and radiation calibrations of SPS prototype and so on have been carried out successively. Firstly, the dispersion optics of SPS covering wavelength from 0.25 to 2.50 μm is designed based on Féry prism principles. The flat-field spectrum moves as the prism rotating within ±2.5°, and is scanned by four exit slits and corresponding photodiodes of different sensitive wavelength ranges. Based on Huygens Point Spread Function (PSF) and linear system theory, a Spectral Response Function (SRF) simulation method is suggested, from which the SPS’s spectral bandpass (FWHM) is derived as being from 1 to 41 nm, and the relationship between the central wavelength of exit slits and prism rotation angle is also deduced. A reference optical path composed of a concave mirror and a linear CCD is designed for precise rotation angle feedback. Secondly, the SPS’s electrical control system consisting of a embedded system and a PC master program is designed. Precise photocurrent detection and fine wavelength scanning are the bases for the SPS’s radiation and wavelength accuracy respectively. A low-noise pre-amplifier circuit is designed, and experiments indicate the SNRs of VNIR1 and VNIR2 spectral channels are greater than 1000. The prism’s fine rotation is achieved by applying a reliable stepper motor driver and a high ratio gear mechanism, and the precise angle feedback is achieved by CCD image process. The rotating resolution reaches 0.8″, and the angle feedback pricision reaches 0.09″. The PC program is designed with debugging, measurement and calibration modes to remotely control the SPS. Finally, wavelength calibration experiments are carried out by using a mercury lamp and a high-resolution grating monochromator. The relationship between wavelength and CCD spot centroid are established respectively for VNIR1 and VNIR2 spectral channels by polynomial fittings, and the calibration uncertainties are estimated to be better than 0.34nm and 0.88nm respectively. The equivalence of wavelength scanning method and prism scanning method for SRF measurement is theoretically analyzed and numerically simulated, and a 632.8nm laser is applied to measure the SRF according to the latter method. The bandpass obtained from scanning 632.8nm laser has a deviation of less than 7% from simulation results. A 1000W standard irradiance lamp is used to carry out the irradiance calibration experiment, with a calibration uncertainty evaluated to be ~3.17%. The measurement uncertainty is evaluated to be ~ 3.18%
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/41498
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	张浩. 基于Fery棱镜分光的太阳光谱仪研究[D]. 中国科学院大学,2014.

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