Thermally-stable wide-spectrum achromatic Doppler asymmetric spatial heterodyne interferometer

Abstract

The invention discloses a thermally-stable wide-spectrum achromatic Doppler asymmetric spatial heterodyne interferometer, relates to the technical field of interference imaging, and aims to realize simultaneous detection of 630nm airglow and 557.7 nm airglow by the Doppler asymmetric spatial heterodyne interferometer, to-be-detected target light is collimated by an image space telecentric objective lens system after passing through an entrance pupil of the interferometer, and then is subjected to optical imaging by an optical imaging system. The collimated light is half-reflected and half-transmitted by the beam splitter and then is divided into two beams with equal intensity, and the two beams respectively enter two branches of the interferometer; wherein one light beam is transmitted through a beam splitter, enters a composite achromatic field-of-view expanding prism through an air interval A1 and enters a harmonic diffraction grating at a Littrow angle theta L, and light beams with different wavelengths are reflected back to the beam splitter from the harmonic diffraction grating at different diffraction angles; and the other light beam is reflected by the beam splitter to enter the branch where the air gap A2 is located, is reflected back to the beam splitter in the same propagation mode, and interferes with the light of the other branch at the beam splitter to form interference fringes, and finally, the interference fringes are imaged on the CCD detector by the detector imaging system.

Description

technical field [0001] The invention relates to the technical field of interference imaging, in particular to a thermally stable wide-spectrum achromatic Doppler asymmetric spatial heterodyne interferometer. Background technique [0002] Atmospheric wind field affects weather changes, flight orbit parameters of various spacecraft, and precise guidance of missiles. Therefore, atmospheric wind field detection is an important means of studying atmospheric science. Since 2006, Doppler asymmetric spatial heterodyne technology has been used to detect middle and upper atmospheric wind fields with the advantages of high sensitivity and high resolution. [0003] The Doppler asymmetric spatial heterodyne interferometer mainly uses the airglow spectral lines carrying atmospheric wind field information in the middle and upper atmosphere as the detection source. The commonly used airglow includes the green line 0('S) of oxygen atoms with a wavelength of 557.7nm. and 630.Onm of oxygen at...

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Problems solved by technology

[0004] Assuming a Doppler asymmetric spatial heterodyne interferometer with N-LAK12 as the prism material to expand the field of view and 630nm as the light source to be measured, if the instrument is used to detect the airglow at 557.7nm, the Littrow angle will deviate from is 0.03°, resulting in a wind speed measurement error of more than 10,000 meters per second, so it is impossible to measure the airglow at 557.7nm

At the same time, due to the use of phase frequency shift to invert the characteristics of wind speed, the detection results are very sensitive to temperature changes, and the Littrow angle deviation caused by temperature will cause a wind speed measurement error of 31.64m / s for every 0.1°C change in temperature, so the instrument needs and Strict system temperature control requirements

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