High-Speed All-Optical Switching in Semiconductor Microcavities via Coherent Control of Excitons
Abstract
We have carried out an extensive series of experiments on coherent control of semiconductor quantum microcavities. In these experiments, a phase-locked femtosecond optical pulse pair is used to excite the lower normal mode (cavity polariton), thereby controlling the reflection of a signal pulse tuned to the upper normal mode. Such a controlled reflection may be used as an all-optical switch with picosecond switching time. We have demonstrated that the effect of the microcavity is to provide a huge enhancement of the coherently controlled response compared to bare quantum wells. We have investigated in detail the microscopic physical processes responsible for the nonlinear optical response; the measured response fits well with theories based on the electron-hole Hamiltonian in the coherent-X(5) and 2nd-Born approximations. The physical limits to the coherent control are determined by excitation-induced dephasing; this limits the applicability of the switch in practical terms. We have discovered that the use of phase-locked excitation pulses is that one can generate novel intraband coherences in the quantum wells, arising from true quantum correlations between the cavity field and the carrier populations. The discovery of this effect was perhaps the first genuinely quantum optical effect observed in semiconductor microcavities.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2001
- Accession Number
- ADA403976
Entities
People
- Theodore B Norris
Organizations
- University of Michigan