Terahertz wave generation device

Abstract

A terahertz wave generating apparatusincludes an excitation light source, a transmission-type diffraction grating, a variable imaging optical system, and a nonlinear optical crystal. The transmission-type diffraction gratinginputs pulsed excitation light output from the excitation light source, and diffracts and outputs the pulsed excitation light. In the transmission-type diffraction grating, its orientation is variable with a straight central axis, that is parallel to the grooves and passing through an incident position of a principal ray of the pulsed excitation light. The variable imaging optical systemis configured to input the pulsed excitation light diffracted to be output by the transmission-type diffraction grating, to form an image of the pulsed excitation light by the transmission-type diffraction grating, and its imaging magnification is variable. The nonlinear optical crystalis disposed at a position at which the pulsed excitation light is formed as the image by the variable imaging optical system, and inputs the pulsed excitation light via the variable imaging optical system, and generates a terahertz wave T. Thereby, a terahertz wave generating apparatus, in which it is easy to adjust a phase matching condition, can be realized.