Abstract

The radiative decay of grating-coupled plasmons in a two-dimensional (2D) electron gas in semiconductor heterostructures is an interesting candidate for a solid-state terahertz (THz) radiation source. We present the first observation of the emission of submillimeter radiation from optically excited coherent two- dimensional plasma oscillations at an AlGaAs/GaAs heterojunction. The surface of the sample is covered with a grating coupler, allowing the coupling of the plasmons to the THz field. The 100- fs pulses from a Ti:sapphire laser strike the sample under an angle of 45°. The emitted THz radiation is detected by time-domain Thz-emission spectroscopy, a technique allowing the selective measurement of coherent (i.e., phase-synchronous) FIR radiation phenomena in the frequency range from 0-4 THz.¹

© 1996 Optical Society of America