High-energy terahertz pulse generating device and method

Abstract

The invention provides a high-energy terahertz pulse generating device and method. The high-energy terahertz pulse generating device comprises a femtosecond laser, a reflecting grating, a half wave plate, an imaging lens and a lithium niobate crystal combined structure, wherein pump femtosecond laser light emitted from the femtosecond laser is diffracted onto the half wave plate; after the polarization direction of the pump femtosecond laser light is changed by the half wave plate, the pump femtosecond laser light enters the lithium niobate crystal combined structure after passing through theimaging lens, and therefore, terahertz pulse radiation is generated in a lithium niobate crystal plate. The lithium niobate crystal combined structure comprises an isosceles triangle shaped prismy lithium niobate crystal and the lithium niobate crystal plate, wherein the base angle of the isosceles triangle shaped prismy lithium niobate crystal is 62-63 degrees; the apical angle of the isosceles triangle shaped prismy lithium niobate crystal is 54-56 degrees; the thickness of the lithium niobate crystal plate is 1-5 mm; the lithium niobate crystal plate completely covers a cylindrical surfaceon which the bottom side of the isosceles triangle shaped prismy lithium niobate crystal is located through an optical contact method; and three cylindrical surfaces of the isosceles triangle shaped prismy lithium niobate crystal are optically polished.

Description

technical field [0001] The present invention relates to the field of optical technology, and more specifically, to a high-energy terahertz pulse generation device and method. Background technique [0002] Terahertz (THz) radiation usually refers to electromagnetic waves from 0.1 to 10 THz, and its wave band is between microwave and far infrared. Due to the special position of terahertz frequency on the electromagnetic spectrum, high-energy light sources in this frequency band are very scarce. According to the size of the device, high-energy terahertz radiation sources can be divided into synchrotron radiation terahertz sources and desktop small terahertz sources. Terahertz sources for synchrotron radiation can produce terahertz pulses on the order of hundreds of microjoules, but such large devices are expensive and expensive to run. Desktop strong-field terahertz radiation sources are mainly driven by pulsed femtosecond lasers, which can be divided into optical rectificati...

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Problems solved by technology

[0008] In order to solve the problem that when femtosecond laser pulses act on lithium niobate crystals to generate high-energy terahertz pulses in the prior art, the excitation light close to the 62-63° angle cut edge of the crystal travels too short in the crystal, and far away from the angle edge The excitation light has a long propagation distance in the crystal, which makes it impossible to further improve the photon energy conversion efficiency from the excitation light to the terahertz wave. A high-energy terahertz pulse generation device and method are proposed

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