Coherent and ultrafast optoelectronics in III-V semiconductor compounds

Abstract

III-V compound semiconductors offer a fascinating multitude of phenomena which have become accessible via ultrafast time-resolved spectroscopy. Coherent vibronic and electronic dynamics are prepared by excitation with taylored femtosecond laser pulses. The analysis of their temporal dephasing or decay provides deep insights into the interaction between electronic and vibronic degrees of freedem and the surrounding bath in high purity quantum structures. In contrast to coherent electronic or vibronic states, deliberately introduced growth defects can be used to drastically shorten the lifetime of optically excited carriers. Sub-picosecond carrier lifetimes open the possibility to realize ultrafast saturable absorbers and optoelectronic transducer elements. They are particularly important as key elements in THz technology, such as efficient THz emitters, detectors, and for on-chip THz technology. This paper summarizes the most distinguished results relevant in the context of ultrafast optoelectronics and THz technology obtained in close collaboration with the Paul-Drude-Institute Berlin over the past decade.