SYSTEM FOR PERFORMING TERAHERTZ WAVE COHERENT DETECTION BY USING LIQUID WATER

摘要

A system for performing terahertz wave coherent detection by using liquid water, comprising a laser (1), a light splitter (2), an optical parametric amplifier (3), a chopper (4), a planar reflection mirror (5), a first convex lens (6), a DAST nonlinear crystal (7), a first off-axis parabolic reflection mirror (8), a terahertz filter (9), a second off-axis perforated parabolic reflection mirror (10), a β-BBO nonlinear frequency doubling crystal (11), an optical wedge pair (12), an α-BBO nonlinear birefringent crystal (13), a half-wave plate (14), a second convex lens (15), a liquid film (16), a third convex lens (17), a bandpass filter (18), a photomultiplier tube (19), and a lock-in amplifier (20). According to the present invention, plasma fluorescent radiation is applied in combination with a coherence principle of a carrying light beam and a second harmonic, and the liquid water is applied to the coherent detection of terahertz waves; thus, the present invention has the advantages of a simple constitution, low construction cost, high stability, strong repairability, and easy maintenance.