Device and method for generating TeraHertz waves with continuous tilting pulse wavfronts based on thin prism group

Abstract

The invention relates to a method for generating TeraHertz waves by using a femtosecond laser optical rectification method, and provides a method for generating the TeraHertz waves through continuouswavefront tilted pumping lithium niobate based on a thin prism group. The continuous tilting pulse wavefronts of the beam-expanded pumping femtosecond pulse are obtained by using the thin prism group,any distortions of time, space and frequency domains are rarely introduced so that the light-TeraHertz wave conversion efficiency can be improved, and the method has the advantages of being low in cost, convenient to adjust, simple, efficient and high in practicability. A device for generating the TeraHertz waves with the continuous tilting pulse wavfronts based on the thin prism group is composed of a femtosecond laser light source, a beam expander, the thin prism group, an imaging lens and lithium niobate crystals, wherein the thin prism group is composed of four small-tip-angle thin rectangular prisms; after the laser pulses generated by the femtosecond laser light source pass through the beam expander, the pulse wavefronts are flat surfaces, then the laser pulses vertically enter thethin prism group and then projected onto the lithium niobate crystals through the imaging lens. The device and the method are mainly used for generating the TeraHertz waves.

Description

technical field [0001] The invention relates to a method for generating terahertz waves by a femtosecond laser optical rectification method, in particular to a method for generating terahertz waves by obliquely pumping lithium niobate on a continuous wave surface based on a thin prism group. Background technique [0002] At present, the use of optical rectification to generate ultrafast terahertz waves is one of the important photonics methods in the field of terahertz technology [1]. The main mechanism of optical rectification to generate ultrafast terahertz waves is to utilize the second-order nonlinear effect of nonlinear crystals. When a femtosecond pulse acts on a nonlinear crystal, the monochromatic components in the pulse no longer propagate independently, but frequency mixing occurs. Among them, the sum frequency effect produces light waves with a frequency close to the second harmonic, and the difference frequency effect produces a low-frequency oscillating electri...

AI Technical Summary

Problems solved by technology

[0007] In addition, it is currently possible to achieve an exact LiNbO 3 The parameters of the diffraction grating required for the oblique pulse wavefront at the exit angle of the crystal prism (the Cherenkov wavefront of the terahertz wave generated in the lithium niobate crystal) are difficult to match with those of the existing commercial gratings

If Custom Gratings Are Expensive

Generally, commercial gratings with similar parameters are purchased, which inevitably introduces tilt angle errors

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