Reflective airy ring diffraction grating

Abstract

A reflective airy ring diffraction grating has a laminated structure and sequentially comprises a substrate layer (2), a metal reflective film layer (3), a semipermeable and semireflective film layer (4) and an antireflection film layer (1) from the top down, wherein the metal reflective film layer is formed by splicing two paired different metal reflective film layers (5 and 6) one by one at intervals in circular and coaxial annular ways; and the refractive index of the semipermeable and semireflective film layer is between the refractive indexes of the two paired metal reflective film layers. The reflective airy ring diffraction grating improves the light intensity uniformity and the boundary sharpness of a focal plane by changing the amplitude and the phase distribution of incident light, is applied to laser operation, laser precise processing and laser irradiation, has very obvious effects of improving the operation precision, the processing precision and the irradiation uniformity, and solves the problem that the precision and the uniformity are poor because a matched grating is not adopted in the fields over the years.

Description

technical field [0001] The invention relates to an optical element, in particular to a grating which can be applied in the fields of laser medicine, laser processing, laser irradiation and the like. Background technique [0002] In the prior art, gratings are not used to control the boundary sharpness and distribution uniformity of the focal spot in the transmission of laser light. Due to the influence of diffraction, the distribution of the spot will change during the transmission of the laser. Even for a laser with relatively high boundary sharpness and uniform distribution, its sharpness and uniformity will deteriorate after a certain distance, especially for the spot that is focused to the focal point. In order to overcome this problem, an Airy ring diffraction grating whose light intensity reflection coefficient shows an Airy ring distribution and has a π jump in the phase at the point where the light intensity is zero is installed at the transmitting end of the laser, ...

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Problems solved by technology

CN101887140 discloses a broadband all-dielectric multilayer reflection diffraction grating and its design method, CN101750650 discloses a multiple diffraction grating, and CN1523591 discloses a wavelength-selective diffraction grating. In terms of grating technology, these patented technologies have made respective contributions to the society , after search and market investigation, no relevant reports and relevant products about Airy ring diffraction gratings applied in the fields of laser surgery, metal precision processing, and laser irradiation have been found.

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