Effects of thermal motion on electromagnetically induced absorption
arXiv:1107.0525 · doi:10.1103/PhysRevA.83.053812
Abstract
We describe the effect of thermal motion and buffer-gas collisions on a four-level closed N system interacting with strong pump(s) and a weak probe. This is the simplest system that experiences electromagnetically induced absorption (EIA) due to transfer of coherence via spontaneous emission from the excited to ground state. We investigate the influence of Doppler broadening, velocity-changing collisions (VCC), and phase-changing collisions (PCC) with a buffer gas on the EIA spectrum of optically active atoms. In addition to exact expressions, we present an approximate solution for the probe absorption spectrum, which provides physical insight into the behavior of the EIA peak due to VCC, PCC, and wave-vector difference between the pump and probe beams. VCC are shown to produce a wide pedestal at the base of the EIA peak, which is scarcely affected by the pump-probe angular deviation, whereas the sharp central EIA peak becomes weaker and broader due to the residual Doppler-Dicke effect. Using diffusion-like equations for the atomic coherences and populations, we construct a spatial-frequency filter for a spatially structured probe beam and show that Ramsey narrowing of the EIA peak is obtained for beams of finite width.
References in corpus (7)
- Storing images in warm atomic vapor
- Diffusion-induced Ramsey narrowing
- Elimination, reversal, and directional bias of optical diffraction
- Inhibition of electromagnetically induced absorption due to excited state decoherence in Rb vapor
- Theory of Thermal Motion in Electromagnetically Induced Transparency: Diffusion, Doppler, Dicke and Ramsey
- Measurement of Dicke Narrowing in Electromagnetically Induced Transparency
- Theory of Dicke narrowing in coherent population trapping