Abstract-Visualization of the internal field in the GaAs-based solar cell under its operating condition with Terahertz radiation

K. Miyagawa, M. Nagai, C. Kim,  H. Akiyama, Y. Kanemitsu, M. Ashida

https://ieeexplore.ieee.org/document/8510084

We demonstrated the visualization of the internal field in a GaAs-based solar cell under its operating condition with evaluating the first half-period of the terahertz (THz) wave emitted by the simultaneous excitation with the weak ultrashort optical pulse and continuous light. We observed the reduction of the internal field with increasing the intensity of the continuous light, which is relevant to the solar cell performance.

Abstract-Coherent detection of THz-induced sideband emission from excitons in the nonperturbative regime

K. Uchida, T. Otobe, T. Mochizuki, C. Kim, M. Yoshita, K. Tanaka, H. Akiyama, L. N. Pfeiffer, K. W. West, and H. Hirori

https://journals.aps.org/prb/accepted/43076O14Z2210330d36f6038100d0aa224fae6d98

Strong interaction of terahertz (THz) waves with excitons induces nonperturtbative optical effects such as Rabi splitting and high-order sideband generation. Here, we investigated coherent properties of THz-induced sideband emissions from GaAs/AlGaAs multi-quantum-wells, and determined the optical susceptibility of the THz dressed exciton in the nonperturbative regime. The strong dependences of both amplitude and phase of the second-order sideband emission on the THz electric field strength imply that the field ionization of the 1s exciton modifies the THz-dressed exciton's energy spectrum.

Abstract-Subcycle Optical Response Caused by a Terahertz Dressed State with Phase-Locked Wave Functions

K. Uchida, T. Otobe, T. Mochizuki, C. Kim, M. Yoshita, H. Akiyama, L. N. Pfeiffer, K. W. West, K. Tanaka, and H. Hirori

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.277402

The coherent interaction of light with matter imprints the phase information of the light field on the wave function of the photon-dressed electronic state. A driving electric field, together with a stable phase that is associated with the optical probe pulses, enables the role of the dressed state in the optical response to be investigated. We observed optical absorption strengths modulated on a subcycle time scale in a GaAs quantum well in the presence of a multicycle terahertz driving pulse using a near-infrared probe pulse. The measurements were in good agreement with the analytical formula that accounts for the optical susceptibilities caused by the dressed state of the excitons, which indicates that the output probe intensity was coherently reshaped by the excitonic sideband emissions.

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