Four-area grating for amplitude/phase dual modulation and its fabrication method

Abstract

The invention discloses a four-area grating for amplitude / phase dual modulation and a manufacturing method thereof, which includes a base, and the base is divided into four areas along a horizontal direction according to a period of the grating; the four areas are from From left to right, they are respectively a high base layer, a high metal layer, a low base layer and a low metal layer; a metal mask layer is arranged on the upper surfaces of the high metal layer and the low metal layer; the low metal layer and the low metal layer The heights of the base layers are different; the total height of the high metal and high base layers is the same. In the present invention, the grating along the horizontal direction is divided into four regions according to one cycle, the lateral widths of the four regions are equal, and the heights of the four regions are different, because the four regions can improve the accuracy of dual control of light intensity and phase , so as to reduce the diffraction efficiency of 0-order light, concentrate the energy to ±1-order, and improve the signal contrast and signal-to-noise ratio of systems such as grating interferometers.

Description

technical field [0001] The invention belongs to the technical field of diffractive optical elements, and in particular relates to a four-region grating for amplitude / phase dual modulation and a manufacturing method thereof. Background technique [0002] With the continuous development of high-precision technology, the demand for some unconventional grating devices is increasing. The existing phase modulation grating mainly has two shortcomings: first, the control accuracy is poor, and the depth of the phase modulation is poor (the efficiency of the 0-level light is not reduced enough, and the efficiency of the ±1-level light is not improved enough); second, the structure is complex , the steepness of the side wall of the step cannot be precisely controlled, etc., which is not conducive to the solidification of the process, so that the phase of the grating cannot be precisely controlled. Although high-precision equipment is used to manufacture, the manufacturing process step...

AI Technical Summary

Problems solved by technology

The existing phase modulation gratings mainly have two disadvantages: first, poor control accuracy and poor depth of phase modulation (the efficiency reduction for 0-order light is not enough, and the efficiency improvement for ±1 order is not enough); second, the structure is complex , The steepness of the side wall of the step cannot be accurately controlled, which is not conducive to process curing, so the phase of the grating cannot be accurately controlled

Although it is manufactured with high-precision equipment, the manufacturing process steps can be precisely controlled, but the processing cost is very high, which is not conducive to mass production; and the phase modulation grating cannot meet the modulation of light intensity at the same time.

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