Far-infrared electromagnetic wave generator

摘要

A far-infrared electromagnetic wave generator comprises a semiconductor containing at least one impurity which has an energy difference, close to a quantum energy of optical phonon, between its transition levels; a resonator having two reflectors for effecting positive feedback of an electromagnetic wave corresponding to the quantum energy; and means for applying an electric current across the semiconductor. The semiconductor may have p-i, n-i, p-i-n, p-n, or n-p- junction. One of the reflectors of the resonator may have a diffraction grating so that the wavelength of the electromagnetic wave to be generated can be varied by adjusting an angle of the diffraction grating.