Low-cut-off frequency hybrid spatial filter

Abstract

The invention discloses a low-cut-off frequency hybrid spatial filter. The low-cut-off frequency hybrid spatial filter comprises a volume Bragg grating, a first focusing lens, a pin hole and a second focusing lens which are arranged in sequence, wherein the volume Bragg grating performs Bragg diffraction on incident light, the first focusing lens performs Fourier transform on the light diffracted by the volume Bragg grating and transforms a light beam from a spatial domain to a frequency domain, second spatial filtering of the light beam is achieved through the pin hole, and the second focusing lens transforms the light beam from the frequency domain to the spatial domain so as to finish spatial filtering. The low-cut-off frequency hybrid spatial filter is completely different from a traditional spatial filter only provided with a lens and a pin hole, and the possibility that focused laser causes the hole stopping effect and enables filtering components and parts to be burned down is reduced. The low-cut-off frequency hybrid spatial filter has low cut-off frequency and low-frequency loss efficiency, has excellent lowpass filtering capacity and is high in bearable laser power.

Description

technical field [0001] The invention relates to the technical field of optical filtering, in particular to a low-cutoff frequency hybrid spatial filter with angle-selective filtering capability, low cutoff frequency, and low frequency loss rate. Background technique [0002] The high coherence of the laser makes it very sensitive to various spatial disturbances, and the diffraction caused by various disturbances will reduce the spatial uniformity of the laser. In the field of advanced laser devices, the small-scale self-focusing effect has become the main reason affecting the near-field quality of the beam, and the load capacity of advanced laser devices has been seriously developed. Improving the near-field uniformity of laser light can help improve the load capacity of advanced laser devices. [0003] In the nearly 40 years since the development of advanced laser devices, although the damage threshold of various optical components has been continuously improved, various b...

AI Technical Summary

Problems solved by technology

There is an unsolvable contradiction. In order to obtain a good enough filtering effect, the small holes of the spatial filter are usually very small; however, due to the divergence angle and spatial modulation of the incident laser beam itself, there is an obvious "skirt" in the far field distribution of the beam. These "skirt" areas interact with the edge of the small hole to produce a "gambling hole effect", which severely limits the diameter design of the small hole and directly leads to a decrease in the filtering ability of the spatial filter

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