Method for producing large area holographic grating based on second exposure of reference grating

Abstract

The invention discloses a preparation method of a large area holographic grating based on reference grating double exposure to prepare diffraction grating; the method comprises the following steps: (1) a reference holographic plate is fixed; (2) a main holographic plate is shielded, the holographic grating recording optical field is used for preparing reference grafting; (3) more non-dense Moire fringe is formed by the reference grafting and the recording grafting, the direction of the Moire fringe is vertical to the line direction of the reference grafting, and the Moire fringe information is recorded; (4) the first part of the main holographic plate is exposed and developed; (5) the main holographic plate and the reference holographic plate are moved simultaneously, the relative position of the reference grafting and the recording optical field is adjusted to lead the reappeared Moire fringe information to be the same as the Moire fringe information in the step (3); and (6) the second part of the main holographic plate is exposed and developed, and the production of holographic exposure splicing grating is finished. The preparation method realizes splicing of adjacent sections in the preparation process of diffraction grating guarantees the parallelism precision and the phase relationship and can be used for preparing the large area diffraction grating.

Description

technical field [0001] The invention relates to a method for preparing an optical element, in particular to a method for preparing a large-area holographic diffraction grating. Background technique [0002] Large-area equidistant one-dimensional diffraction gratings are the key components of many large-scale high-tech engineering projects. At present, in the laser confinement nuclear fusion system, the equidistant and flatness precision of the one-dimensional diffraction grating lines is extremely high. Holographic technology is a very important technical means to manufacture large-aperture diffraction gratings, and the aperture of diffraction gratings is limited by the aperture of the holographic recording optical system. In order to manufacture a holographic grating with an ultra-large aperture, people hope to make a large-area holographic grating by splicing multiple gratings. Large-area holographic grating splicing can be divided into two directions: holographic exposu...

AI Technical Summary

Problems solved by technology

In the mechanical splicing method, in order to ensure the parallel accuracy and phase relationship between the grating lines, a special micro-positioning mechanism is designed. However, this mechanism structure is difficult to ensure the stability of the grating for a long time after splicing, and the engineering practicability is limited.

Holographic exposure splicing can realize large-area grating production, and the resulting grating is very stable, but the splicing process is difficult. In the splicing process, it is necessary to solve the alignment problem of the stripes, that is, the fringe of the second grating is consistent with the first grating. The stripes of the block grating must be parallel, and the interval between them must be an integer multiple of the grating period

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