Nonlinear frequency conversion crystal

Abstract

The embodiment of the invention provides a nonlinear frequency conversion crystal. The nonlinear frequency conversion crystal comprises an incident plane, a first inclined plane, a second inclined plane and a spherical surface, wherein the phase matching direction of the crystal is parallel to the central axis of the crystal, the incident plane is vertical to the central axis, the first inclined plane and the second inclined plane are arranged on two sides of the central axis oppositely, and an inclined angle between the first inclined plane and the central axis and an inclined angle between the second inclined plane and the central axis are the same; the spherical surface is connected with the first inclined plane and the second inclined plane respectively, and the center of a sphere of the spherical surface is positioned on the central axis. According to the crystal provided in the embodiment of the invention, two times of frequency conversion are realized on a return path, and moreover, one time of focusing is realized in the process of realizing frequency conversion every time, so that the frequency conversion efficiency can be greatly improved, and the proportion of light beams after frequency conversion in light beams emitted from the incident surface of the crystal is increased finally.

Description

technical field [0001] Embodiments of the present invention relate to the technical field of nonlinear frequency conversion, and more specifically, relate to a nonlinear frequency conversion crystal. Background technique [0002] At present, the laser wavelength required in many practical applications cannot be directly generated by the stimulated radiation laser medium, and must be obtained by laser frequency conversion technology. The output wavelength of lasers based on nonlinear frequency conversion technology has covered the deep ultraviolet to mid-far infrared band, and due to the absorption, transmission and response properties of certain substances to specific wavelengths, people's demand for special wavelength lasers is increasing day by day. For example: third harmonic generation (Third Harmonic Generation, THG) can be performed on a picosecond laser with a wavelength of 1064nm to obtain an ultraviolet laser with a wavelength of 355nm, which can be applied to the p...

AI Technical Summary

Problems solved by technology

Although it can be focused multiple times to increase the peak power of the fundamental frequency light, the signal light generated by the frequency conversion of the fundamental frequency light in the first crystal propagates in the free space between the crystals, which will cause the signal light generated in the first crystal There is a phase difference between the signal light and the signal light generated in the second crystal, resulting in coherence and phase cancellation, which greatly reduces the frequency conversion efficiency; at the same time, it is difficult to accurately and real-time control the two beams of signal light to have the same phase

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