Fast Scanning Optical Delay Line Based on Helical Step Mirror

Abstract

The invention discloses a fast-scanning optical delay line based on a spiral stepped reflector, which includes a spiral stepped reflector and a motor. The spiral stepped reflector is in an irregular cylindrical shape, and one end surface of the cylindrical shape is a plane structure perpendicular to the generatrix of the cylinder. One end face is a plurality of small plane reflectors arranged in steps along the circumference, the small plane reflectors are parallel to one end face of the cylindrical planar structure, and the distance between the mirror surface of the small plane reflector and the one end face of the cylindrical planar structure is Arranged in an arithmetic sequence, the spiral stepped reflector is installed on the output shaft of the motor, and the spiral stepped reflector is driven by the motor to rotate around the axis of the cylinder. The fast scanning optical delay line based on the spiral stepped reflector of the present invention has a fast scanning speed and a good structure. It is compact, has high repeatability, no distortion, simple processing technology, and can work continuously and stably for a long time, which will help promote the practical application of the terahertz time-domain spectroscopy measurement system.

Description

Technical field [0001] The invention relates to the technical field of terahertz spectrum measurement, and relates to the problem of shortening the spectrum measurement time of a terahertz time-domain spectrum measurement system, and specifically refers to a fast scanning optical delay line based on a spiral staircase mirror. Background technique [0002] Terahertz waves refer to electromagnetic waves with a frequency between 0.1THz and 10THz, which have low photon energy, strong penetration of non-polar materials, good instantaneity, large bandwidth, simultaneous measurement of amplitude and phase information, and high signal-to-noise ratio , Photon energy is in the vibrational energy level and rotational energy level of many biological macromolecules, and the interaction energy level between molecules. The terahertz time-domain spectroscopy measurement system made by using the above characteristics of terahertz can measure the spectral information of dielectric materials, semic...

AI Technical Summary

Problems solved by technology

[0004] (1) Because the reflective surface of the inclined parabolic bus helicoid reflector is a curved surface, the reflected light is distorted;

[0005] (2) There is an angle between the incident light and the reflected light, and it is necessary to arrange a back-facing reflector on the reflected light path of the inclined parabolic bus helicoid reflector to make the light path return along the original path, resulting in an uncompact system structure;

[0006] (3) Because the surface of the inclined parabolic busbar helical reflector is a curved surface, and the optical reflector has high requirements for the mirror surface, the processing precision of the mirror surface is extremely high, and the processing cost is expensive;

[0007] (4) Since the center of gravity of the asymmetric mirror is not on its rotation axis, when the motor drives high-speed rotation, vibration will be generated, which will lead to unstable operation of the optical delay line

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