Effects of thermal motion on electromagnetically induced absorption

Journal Article · Sun May 15 00:00:00 EDT 2011 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.83.053812· OSTI ID:21546861

Tilchin, E; Wilson-Gordon, A D; Firstenberg, O ^[1]

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1. Department of Chemistry, Bar-Ilan University, Ramat Gan IL-52900 (Israel)

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 state to the 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 the 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 diffusionlike 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.

• OSTI ID: 21546861
• Journal Information: Physical Review. A, Vol. 83, Issue 5; Other Information: DOI: 10.1103/PhysRevA.83.053812; (c) 2011 American Institute of Physics; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION
ABSORPTION SPECTRA
APPROXIMATIONS
ATOMS
BEAMS
COLLISIONS
DIFFUSION EQUATIONS
DOPPLER BROADENING
ELECTROMAGNETIC FIELDS
EMISSION
EXCITED STATES
GROUND STATES
MATHEMATICAL SOLUTIONS
PEAKS
PROBES
PUMPING
CALCULATION METHODS
DIFFERENTIAL EQUATIONS
ENERGY LEVELS
EQUATIONS
LINE BROADENING
PARTIAL DIFFERENTIAL EQUATIONS
SORPTION
SPECTRA