Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE
Ultrafast manipulation of coherent excitons using ultrashort-pulse sequences prepared by frequency domain shaping
Kazuhiro Komori, Takeyoshi Sugaya, Masanobu Watanabe
Abstract
In this paper, we report ultrafast manipulation of coherent excitons in quantum-wells using phase locked pulse sequence prepared by a frequency domain shaping technique. The pulse shaping system with double liquid crystal spatial light modulator (SLM) and the Ti3+-sapphire laser are used to generate phase-locked pulses. Ultrafast coherent control of exciton population and exciton polarization is demonstrated by the observation of the reflectivity-change in the pump-probe and the diffracted power in the degenerate-four-wave-mixing measurements. In the single quantum wells, good coherent control characteristics with 87% of coherent carrier destruction is demonstrated at low excitation power of 0.15 mW (approximately 1.1 X 1010 photons/cm2). Also the preliminary manipulation of the exciton population is demonstrated by the phase locked multi-pulses. In case of coupled quantum-wells, the modulation of SLM is carefully controlled and coherent control of both the exciton population and the polarization are demonstrated in the two different coupled quantum well samples.