D. Grischkowsky, N.S. Shiren, et al.
Applied Physics Letters
Using a high-performance optoelectronic THz beam system for time-domain spectroscopy, we have measured the absorption and index of refraction of N- and P-type doped GaAs from low frequencies to 4 THz. From these measurements the complex conductance was obtained over the same frequency range. All of the results were well fit by Drude theory.