Abstract

We demonstrate here that it is experimentally practical to employ the real­time THz probes to access an equilibrium electron gas in a semiconductor heterostructure at a low temperature and magnetic field, and study the response of a 2D electron gas to picosecond transient electric fields in an n-type MQW GaAs/GaAlAs structure. The experimental arrangement is shown in the upper trace of Figure 1. The collimated beam passes a free standing wire grid polarized and is subsequently focused inside a superconducting magnet onto a sample (with a spot size of approximately 6 mm). The crossed polarizer (power) extinction ratio was about 4x10^-4. The average power in the THz beam was measured by a bolometer to be approximately 1 nW, corresponding to an average flux of 10⁴-10⁵ photons/cm² per pulse incident of the samples.

© 1993 Optical Society of America