SPECTRAL LINE NARROWING IN ELECTROMAGNETICALLY INDUCED TRANSPARENCY

摘要

Electromagnetically induced transparency (EIT) can make an otherwise opaque medium transparent by utilizing quantum coherence. EIT has attracted great interest since the 1990s for its wide applications in metrology, nonlinear and quantum optics, and quantum information science. We present a review on spectral line narrowing mechanisms in EIT-related systems, accounting for linewidths much narrower than expected from the standard mechanisms of Doppler broadening, transit time broadening, magnetic field inhomogeneity and power broadening. Topics covered include Dicke narrowing, atomicmotion-induced Ramsey narrowing, motional narrowing, density narrowing, laser in_duced narrowing and power-broadening-free resonance. Intuitive pictures are provided to describe the essential physics of each mechanism.