Theory of Dicke narrowing in coherent population trapping

Journal Article · Sun Jul 15 04:00:00 EDT 2007 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.76.013818· OSTI ID:21011314

Firstenberg, O; Shuker, M; Ben-Kish, A; Ron, A ^[1]; Fredkin, D R ^[2]; Davidson, N ^[3]

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1. Department of Physics, Technion-Israel Institute of Technology, Haifa 32000 (Israel)
2. Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States)
3. Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100 (Israel)

The Doppler effect is one of the dominant broadening mechanisms in thermal vapor spectroscopy. For two-photon transitions one would naively expect the Doppler effect to cause a residual broadening, proportional to the wave-vector difference. In coherent population trapping (CPT), which is a two-photon narrow-band phenomenon, such broadening was not observed experimentally. This has been commonly attributed to frequent velocity-changing collisions, known to narrow Doppler-broadened one-photon absorption lines (Dicke narrowing). Here we show theoretically that such a narrowing mechanism indeed exists for CPT resonances. The narrowing factor is the ratio between the atom's mean free path and the wavelength associated with the wave-vector difference of the two radiation fields. A possible experiment to verify the theory is suggested.

• OSTI ID: 21011314
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 1 Vol. 76; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION
ATOMS
DOPPLER BROADENING
DOPPLER EFFECT
LINE NARROWING
MEAN FREE PATH
MULTI-PHOTON PROCESSES
PHOTON-ATOM COLLISIONS
PHOTONS
RADIATION PRESSURE
RESONANCE
SPECTROSCOPY
TRAPPING
VAPORS
VELOCITY
WAVELENGTHS