Mixing of two optical beams with close frequencies in photoconductive structures or their response to ultrashort optical pulses are widely used for the generation of terahertz (THz) electromagnetic radiation. The THz radiation produced by optically excited plasma oscillations in p-i-n structures has been observed by some teams. In this communication, we consider a heterostructure akin to a field-effect transistor with high electron mobility in its two-dimensional channel and report on the modeling of THz oscillations caused by optical signals in this heterostructure. The features of such a heterostructure are associated with the existence of weakly damped electron plasma oscillations and possibility of their resonant excitation, so that the two-dimensional electron channel serves as a resonant cavity with rather high quality factor. A conception of THz photomixing using the excitation of standing plasma waves (plasma oscillations) in the heterostructure under consideration has recently been proposed by the authors. We demostrate that due to the excitation of the electron plasma oscillations in the channel by the photogenerated electrons and holes, the heterostructure in question exhibits a pronounced resonant response leading to high amplitudes of the ac photocurrent oscillations. As shown, this can result in substantially higher efficiency of the THz radiation generation by optical signals than that in p-i-n structures.

Date Published: 29 April 2003
PDF: 6 pages
Proc. SPIE 5118, Nanotechnology, (29 April 2003); doi: 10.1117/12.498875

Published in SPIE Proceedings Vol. 5118:
Nanotechnology
Robert Vajtai; Xavier Aymerich; Laszlo B. Kish; Angel Rubio, Editor(s)