Publications

Detection of ultrafast THz pulses via electro-absorption in coupled asymmetric quantum wells

Li, Chia Y.; Seletskiy, Denis V.; Cederberg, Jeffrey G.; Sheik-Bahae, Mansoor

We utilize quantum-confined Stark-effect in asymmetric double quantum wells (ADQW) to realize coherent detection of broadband THz pulses. For that, broadband THz transients formed by a two-color air plasma are focused onto ADQW, in turn dynamically shifting the ADQW bands, with the bandedge at ∼ 825 nm. Spectrally-resolved detection scheme analyzes absorption modulation signatures imprinted onto the transmitted NIR probe spectrum. Use of only few micron thick samples ensures large detection bandwidth, currently demonstrated up to ∼ 15 THz. Time-domain analysis of this signal shows pronounced bi-polar (coherent) as well as small unipolar components of the signal. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).