Coherent control of terahertz generation in a DC-biased semiconductor microcavity

It is shown that shaped optical pulses may be used to control coherently a novel type of terahertz pulse generation from a planar semiconductor microcavity biased by a DC electric field. The new terahertz signal is due to optical rectification arising from the time-dependent polarization associated with mode oscillations. To make short terahertz pulse trains and simultaneously coherently depopulate the quantum well of excitons, specially tailored square optical pulses with nonzero area are optimal. The coherent depopulation is a strong-coupling effect and is due to the /spl pi/ phase shift in the self-consistent field (i.e., including the local-field effect associated with the exciton resonance) in the cavity that occurs in the course of a mode oscillation.