Two-channel Doppler heterodyne interferometer

Abstract

The invention provides a two-channel Doppler heterodyne interferometer. The Doppler heterodyne interferometer aims at achieving the measurement of two central wavelength target spectral lines. The interferometer comprises an interferometer entrance pupil, a collimating system, a beam splitter prism, a blazed grating component, a stripe imaging system and a detector array. The core component of the beam splitter prism is a depolarization beam splitting film in a 50-to-50 half-reflective and half-transparent mode. The stripe imaging system comprises a front lens group and a back lens group, and a narrow-band filter switching device is arranged between the collimating system and the beam splitter prism. The blazed grating component includes that a first blazed grating, a second blazed grating, a third blazed grating and a fourth blazed grating are respectively arranged on a reflected light way. A Littrow angle is formed by the working face normals of the four blazed gratings and the corresponding incident optical axis, wherein, a working grating is formed by the first blazed grating and the third blazed grating, and another working grating is formed by the second blazed grating and the fourth blazed grating so that the interference of individual wavelength is achieved. The corresponding grating working surface center of the working grating forms an optical path difference of the interferometer along the difference between the distances of the center of the beam splitter prism.

Description

technical field [0001] The invention relates to a Doppler heterodyne interferometer. Background technique [0002] 1. Mathematical expression of the basic principle of Doppler heterodyne interferometer [0003] The measurement medium of atmospheric wind field is the spectral line of atmospheric particles carrying wind field information. According to the Doppler effect, when atmospheric particles move with the atmosphere, the center frequency of the spectral line will shift in frequency, that is, Δλ / λ=Δσ / σ=v / c. According to the above relationship, the motion speed of the atmosphere can be retrieved by detecting the Doppler frequency shift of the particle radiation. [0004] The Doppler heterodyne interferometer uses two blazed gratings to replace the plane mirrors of the two arms of the Michelson interferometer, and introduces a certain basic optical path difference Δd between the two arms of the interferometer. Angle β (the size of β is related to the wavenumber σ), the t...

AI Technical Summary

Problems solved by technology

The commonly used ground-based passive atmospheric wind field measurement interferometer (Fabry-Perot interferometer) can measure the Doppler frequency shift of the target spectral line at two center wavelengths, but the Fabry-Perot interferometer requires high processing and assembly technology, and the instrument The stability is not ideal

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