Development of Cryogenic Far-Infrared Fourier Transform Spectrometer with High Spectral Resolution

远红外傅里叶变换光谱仪应在低温下工作，以避免其自身的热辐射。而远红外天文学的最佳途径是在没有大气辐射和吸收的空间进行观测。本课题的研究目标是研制在这些特殊条件下具有高光谱分辨率的傅里叶变换光谱仪，由于傅里叶变换光谱仪是基于双光束干涉仪的，因此需要精密的位移传感器来参考光程差。远红外傅里叶变换光谱仪中的位移传感器需要在低温下工作。例如，位移传感器的所需规格是具有几微米精度的40 mm总位移。为了达到这一要求，我们采用了干涉扫描头的光学秤。当然，这种类型的水垢的商业等级在低温下不起作用。我们修改了传感器头模块的部分，并将传感器芯片替换为低温部件。最后，我们研制了一种精度为1 μ m，位移量为40 mm的低温位移传感器，在低温条件下，利用我们研制的傅里叶变换光谱仪可以拍摄干涉图。通过研究，为低温远红外傅里叶变换光谱仪的研制奠定了基础。

Far-Infrared Fourier transform spectrometer should be operated at cryogenic temperature to avoid the thermal emission from itself. And the best way for far-infrared astronomy is the observation in space where is free from the atmospheric absorptions and emissions. The goal of this research is to develop the Fourier transform spectrometer with high spectral resolution under these unusual conditions.Since Fourier transform spectrometer is based on two beams interferometer, the precise displacement sensor is required to refer optical path difference. The displacement sensor for far-infrared Fourier transform spectrometer should be worked at cryogenic temperature. For example, required specification of a displacement sensor is 40 mm total displacement with a few micrometers accuracy. To achieve this requirement we adopt the optical scale with interferential scanning head. The commercial grade of this type of scale, of course, does not work under cryogenic temperature. We modify the part of the sensor head module and replace the sensor chips with cryogenic parts. Finally, we have developed the cryogenic displacement sensor for 40 mm displacement with 1 micrometer accuracy.We can take interferograms using our Fourier transform spectrometer with this displacement sensor at cryogenic temperature. The fundamental techniques to construct the cryogenic far-infrared Fourier transform spectrometer are established through this research.