THz wave generating device based on optical rectification Cherenkov effect

Abstract

The invention discloses a THz wave generating device based on an optical rectification Cherenkov effect. The THz wave generating device based on the optical rectification Cherenkov effect is characterized in that the THz wave generating device comprises a femtosecond laser device, a cylindrical lens, a crystal-silicon prism array coupling body, a pneumatic infrared detector, a detecting unit and a time delay system. The femtosecond laser device is a full-automatic integrated broadband femtosecond laser device, the band width and the central wavelength of the femtosecond laser device can be adjusted automatically, the femtosecond laser device outputs optical pulses, the central wavelength of the optical pulses is 800nm, the optical pulses are in horizontal polarization, the space mode of the optical pulses is TEM00, the pulse width of the optical pulses is 18fs, and the diameter of beams is 2mm. The coupling body comprises a crystal and a plurality of blocky silicon prisms, the crystal is a slice-shaped cuboid, and all the silicon prisms are fixed on the upper surface and the lower surface of the crystal. The detecting unit comprises a detecting crystal and a phase-locked amplifier. The time delay system is matched with the detecting unit to carry out the measurement of the THz spectrum. The THz wave generating device based on the optical rectification Cherenkov effect improves the efficiency of converting pump light into THz waves, enlarges the effective acting distance of the optical pulses and the crystal, lowers the limitation to the coupling output of the THz waves, and improves the output efficiency of the THz waves.

Description

technical field [0001] The invention relates to a THz wave generating device based on the optical rectification Cherenkov effect. Background technique [0002] THz waves have many characteristics such as wide frequency bandwidth, good directivity, small scattering, and high spatial resolution. THz science and technology have shown broad application prospects in the fields of material analysis, communication, and investigation, and have become a very attractive research field. Among them, THz wave generation technology is the most critical research content, which is the prerequisite for the application of THz wave in practice. [0003] Photonics-based THz wave generation technology can achieve high-frequency broadband and high-coherence THz wave output at room temperature. The methods include optical rectification effect, optical parametric oscillation, optical difference frequency, etc. These methods are mainly based on the interaction between laser and nonlinear crystal, t...

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Problems solved by technology

[0007] The above scheme has the following disadvantages: since the silicon prism bonded on the upper and lower surfaces of the crystal is a monolithic silicon prism, there are two problems

On the one hand, this solution requires the bottom surface of the prism to be closely bonded to the surface of the crystal, so it is required to polish the bottom surface of the silicon prism (the contact surface with the crystal). However, polishing a large-area silicon prism is very difficult in the process and cannot be guaranteed The flatness of the surface; on the other hand, because the silicon material also has a certain absorption on the THz wave, and the THz wave generated in the crystal needs to be transmitted in the prism for a long distance before it can be output to the free space, so the silicon prism will cause THz waves. attenuation

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