The saturation properties of terahertz emission from biased, large-aperture photoconductors excited by trains of amplified femtosecond optical pulses are presented. A direct comparison is made of the multiple-pulse saturation properties of terahertz emission from semi-insulating GaAs and low-temperature-grown GaAs emitters with different carrier lifetimes. When the carrier lifetime is less than or comparable with the interpulse spacing, a significant enhancement of the narrow-band terahertz output is observed. The enhancement is not observed for emitters with long carrier lifetimes, consistent with the results of a previously derived saturation theory [Opt. Lett. 18, 1340 (1993)].
© 1999 Optical Society of America
(320.7080) Ultrafast optics : Ultrafast devices
(320.7100) Ultrafast optics : Ultrafast measurements
(320.7130) Ultrafast optics : Ultrafast processes in condensed matter, including semiconductors
(320.7160) Ultrafast optics : Ultrafast technology
C. W. Siders, J. L. W. Siders, A. J. Taylor, S.-G. Park, M. R. Melloch, and A. M. Weiner, "Generation and characterization of terahertz pulse trains from biased, large-aperture photoconductors," Opt. Lett. 24, 241-243 (1999)