X-valley influence on hot free electron absorption and optical nonlinearities at 10.6 µm in highly doped n-GaAs

¹ Institute of Radio Engineering and Electronics of RAS, Vvedensky Square 1, 141120 Fryazino (Moscow reg.), Russia
² Vrije Universiteit Brussel, Lab for Micro- and Optoelectronics, Electronics Department, Pleinlaan 2, 1050 Brussels, Belgium

Corresponding author: jstiens@vub.ac.be

Received: 18 December 2001
Revised: 21 February 2002
Accepted: 11 March 2002
Published online: 28 June 2002

Abstract

A theoretical overview is given about the influence of the presence of the X-valley in highly doped n-GaAs on hot free-electron absorption and optical nonlinearities at 10.6 μm wavelength. The implications of the extension of the quantum-mechanical model from two to three valleys are discussed. For electron temperatures above 600 K the X-valley presence starts to be observed. We reveal that it is difficult to trace the individual contributions of different X-electron related inter- and intravalley absorption and relaxation phenomena and therefore we suggest to introduce an effective X-valley related deformation potential which is a weighted combination of all the X-valley contributions. We discuss how nonlinear optical experiments can be conducted to determine the LL-intervalley and this effective X-valley deformation potential.