Physical Review Letters
Laser-Induced Quantum Coherence in a Semiconductor Quantum Well
G. B. Serapiglia, Emmanuel Paspalakis, Carlo Sirtori, Konstantin L. Vodopyanov, Chris C. Phillips
Abstract
The phenomenon of electromagnetically induced quantum coherence is demonstrated between three confined electron subband levels in a quantum well which are almost equally spaced in energy. Applying a strong coupling field, two-photon resonant with the 1-3 intersubband transition, produces a pronounced narrow transparency feature in the 1-2 absorption line. This result can be understood in terms of all three states being simultaneously driven into "phase-locked" quantum coherence by a single coupling field. We describe the effect theoretically with a density matrix method and an adapted linear response theory.