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Kono, Nanase; Itakura, Ryuji; Tsubouchi, Masaaki
no journal, ,
We realize a relativistic Doppler reflection of terahertz (THz) light from a counter propagating photo-induced carrier in silicon (Si). We have observed the Doppler reflection of THz light at some different pump light intensity. The up-shift frequency was increasing with pump intensity, and becoming a constant at high pump intensity. We have defined a new parameter, effective carrier thickness, and discussed the interaction between the photo induced carriers and THz light.
Kono, Nanase; Itakura, Ryuji; Tsubouchi, Masaaki
no journal, ,
Plasma is generated when semiconductors are photo-excited, and it reflects a THz light if a density of free electrons is sufficiently high. Plasma acts as a flying mirror with a velocity which is identical to that of pump light because plasma is generated with a proceeding of pump light into a semiconductor. Then, a counter-propagating THz light is up-shifted via relativistic Doppler reflection. In this study, sample semiconductor is silicon, and we investigated a Doppler reflection of THz light by observing an intensity spectrum and waveform of THz light. From the pump energy dependence, phase and frequency shifts of THz light is increased with pump energy. We constructed a model in consideration of phase shift and Doppler reflection.