Terahertz Transient Spectroscopy of Small Semiconductor Structures

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9417502 Nurmikko This poject concentrates on research in which high speed optical and optoelectronic techniques are applied to the study of lower dimensional electronic excitations in small heterostructures in compound semiconductors. In particular, new terahertz transient spectroscopic methods will be applied to the study of few and many electron systems in quantum wires and dots in quantizing magnetic fields, with emphasis on the ballistic and coherent response. Enhanced spatial resolution in high amplitude THz fields will be provided by near field imaging methods. % % % This project aims at the study of electrom motion in small semiconductor structures, on a scale much smaller than a micrometer. The electrons may be confined along a very thin wire or in a box, this will make them behave more as waves rather than particles. Ultrashort laser pulse techniques are applied to provide an initial impact of excitation of the electrons and to follow their subsequent motion on a timescale of about one trillionth of a second. In particular, a novel spectroscopic arrangement that uses so-called terahertz techniques will be employed. ***