Device for exciting waterline by laser to generate high-strength broadband terahertz waves

Abstract

The invention provides a device for exciting a waterline by laser to generate high-strength broadband terahertz waves. The device comprises a femtosecond laser, a spectroscope, a BBO crystal, a chopper, a reflector, a high numerical aperture microscope objective lens and a waterline, wherein the femtosecond laser is used for emitting lasers with the wavelength of 800 nm, the lasers with the wavelength of 800 nm form a beam of pump light and a beam of probe light through the spectroscope, and the pump light passes through the BBO crystal to generate frequency doubling light with the wavelengthof 400 nm; the 800nm and 400nm mixed double-color laser passes through the chopper, enters the objective lens of the high numerical aperture microscope through the reflector and then is focused on thewaterline, and a radiation source capable of radiating high-intensity broadband terahertz waves outwards is generated on the waterline. According to the invention, the water line emitted by the high-pressure water pump reduces the absorbability of water to terahertz waves and solves the problem of medium threshold damage. Meanwhile, compared with a water film, the waterline is not prone to causing medium breakage due to too high laser energy, and stability is better.

Description

technical field [0001] The present invention relates to the fields of terahertz excitation, laser and hydrodynamics, in particular to the principle and method of laser exciting waterlines to generate high-intensity broadband terahertz waves. Background technique [0002] As a special electromagnetic wave, terahertz wave has a frequency range of 0.1-10THz and a wavelength between millimeter wave and far infrared (30μm-3mm). It has many more unique characteristics than electromagnetic waves in traditional bands. The terahertz spectrum corresponding to the substance also contains a large amount of physical and chemical information of the substance. Therefore, terahertz, an emerging subject frontier technology, has attracted widespread attention, and high-intensity broadband terahertz radiation sources are one of the first conditions for terahertz technology to be put into practical life. In recent years, with the research on terahertz sources, it has been proved that solid cr...

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Problems solved by technology

However, in the water film medium, although the intensity of terahertz wave radiation can be increased to a certain extent by increasing the laser pulse energy and pulse duration, as the excitation laser energy exceeds a predetermined threshold, the laser pulse wave and plasma will eventually expand. Causes the water film to break and the stability is relatively poor

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