Method and device of enhancing terahertz wave signals based on hollow metal waveguide optical fiber

A method of enhancing terahertz wave signals based on a hollow metal waveguide, comprising:

• setting up a device of enhancing terahertz wave signals based on the hollow metal waveguide;
• splitting an incident laser with a wavelength of 800 nm emitted by a laser source into a first laser beam as transmitted laser and a second laser beam as reflected laser;
• sequentially reflecting the transmitted laser with a wavelength of 800 nm by a group of plane mirrors and converging by a first convex lens to enter into a BBO crystal and partially converted into a laser with a wavelength of 400 nm;
• wherein lasers output from the BBO crystal have wavelengths of both 800 nm and 400 nm;
• the reflected laser with a wavelength of 800 nm passes through a first plane mirror, an adjustable delay system, a second plane mirror and a second convex lens, and generates a fixed time phase delay with the lasers having wavelengths of 800 nm and 400 nm output from the BBO crystal;
• all the reflected lasers with a wavelength of 800 nm and the lasers having wavelengths of 800 nm and 400 nm pass through a beam-combination mirror to be converged into the hollow metal waveguide filled with dry gas;
• focuses of the transmitted laser and the reflected laser converged by the first and second convex lenses are located at an entrance of the hollow metal waveguide;
• terahertz waves output from the hollow metal waveguide are collected by a parabolic mirror, and then entered into a detection system;
• turning on the laser source;
• wherein 800 nm and 400 nm laser pulses output from the BBO crystal are overlapped with each other in the hollow metal waveguide, as the first laser beam;
• ionizing gas medium to radiate the terahertz waves in forward propagation;
• as the propagation distance increases, the corresponding 800 nm laser and the 400 nm laser are gradually separated from each other in the time axis;
• adjusting the delay system to delay the reflected laser with a wavelength of 800 nm as the second laser beam;
• wherein when the 800 nm laser pulses in the first laser beam are completely separated from the 400 nm laser pulses, the reflected laser with a wavelength of 800 nm as the second laser beam begin to overlap with the 400 nm laser pulses, which can continuously generate the terahertz waves;
• and
• collecting the terahertz waves output from the hollow metal waveguide by the parabolic mirror;
• wherein the collected terahertz waves are entered into the detection system.