Publications

This paper explores quantum-coherence phenomena in a semiconductor quantum-dot structure. The calculations predict the occurrence of inversionless gain, electromagnetically induced transparency, and refractive-index enhancement in the transient regime for dephasing rates typical under room temperature and high excitation conditions. They also indicate deviations from atomic systems because of strong many-body effects. Specifically, Coulomb interaction involving states of the quantum dots and the continuum belonging to the surrounding quantum well leads to collision-induced population redistribution and many-body energy and field renormalizations that modify the magnitude, spectral shape, and time dependence of quantum-coherence effects.

We generate optical vortex beams in a nanosecond optical parametric oscillator based on an image-rotating resonator. This efficient new method of vortex generation should be adaptable to pulsed or continuous lasers.

We present numerical modeling and laboratory studies of degenerate type I nanosecond optical parametric oscillators. Because the signal and idler waves are identical and parametric gain is phase sensitive, their round-trip phase is a critical parameter. We show that signal spectrum, transverse mode, and conversion efficiency are all strongly influenced by this phase. We also examine the influence of signal-wave injection seedine and phase-velocity mismatch. © 2003 Optical Society of America.