Blazed-grating-based quick small angle identification method

Abstract

The invention, which belongs to the field of intelligent monitoring, provides a blazed-grating-based quick small angle identification method. On the basis of spectral characteristics of a first-orderdiffraction spectrum sequence of a blazed grating, quick identification of a small angle is carried out. With a Y type fiber self-alignment system, identification of a rotation angle change, being angular displacement, of a blazed grating is realized. The method comprises the following steps: establishing a Y-type-fiber-based self-collimation optical path angular displacement identification system; on the basis of a Fraunhofer diffraction principle, obtaining light intensity distribution of corresponding blazed gratings under different wavelengths on different angular displacement conditions by using a numerical simulation method and determining a blazed grating diffraction spectrum characteristics and angular displacement relationship; and putting forward a two-blazed-grating-based differential angular displacement identificaiton principle and system and determining an angular displacement identification method based on differential double-blazed-grating diffraction spectrum cross-correlation spectral analysis. The method has a simple structure; identification is done rapidly; with the differential structure, the sensitivity is improved and the external interference is reduced.

Description

technical field [0001] The invention belongs to the field of sensing, and specifically proposes a method for quickly identifying small angles based on a blazed grating. Background technique [0002] Diffraction gratings are widely used in different fields such as spectroscopy, radio astronomy, integrated optics, optical communication, information processing and precision metrology. The intensity of the spectral lines at all levels of an ordinary diffraction grating decreases with the increase of the order, especially the zero-order without dispersion accounts for most of the light energy, while the intensity of the non-zero-order spectrum actually used is relatively weak. The blazed grating forms an angle between the groove surface and the grating surface, which is the so-called blaze angle, so that the central main maximum of the diffraction diffraction of a single groove surface and the interference zero-order main maximum of the groove surfaces are separated, and the ligh...

AI Technical Summary

Problems solved by technology

However, the optical path adjustment required by these methods is cumbersome, and the optical components need precision processing

In China, variable pitch gratings are also used for angle recognition. The principle is to use the change of the pitch of the blazed grating at different positions to filter broadband polychromatic light. The grating with this characteristic is made into a cylindrical shape, thereby Realize the recognition of different rotation angle displacements, but the development of variable pitch gratings is difficult and costly

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