Europhys. Lett.
Volume 72, Number 4, November 2005
Page(s) 562 - 568
Section Electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics
Published online 14 October 2005
Europhys. Lett., 72 (4), pp. 562-568 (2005)
DOI: 10.1209/epl/i2005-10277-9

Coherent population trapping in quantized light field

A. V. Taichenachev, A. M. Tumaikin and V. I. Yudin

Novosibirsk State University - Pirogova 2, Novosibirsk 630090, Russia and Institute of Laser Physics, SB RAS - Lavrentyeva 13/3, Novosibirsk 630090, Russia

received 6 June 2005; accepted in final form 21 September 2005
published online 14 October 2005

A full quantum treatment of coherent population trapping (CPT) is given for a system of resonantly coupled atoms and electromagnetic field. We develop a regular analytical method of the construction of generalized dark states (GDS). It turns out that GDS do exist for all optical transitions $F_g\to F_e$, including bright transitions $F\to
F+1$ and $F''\to F''$ with F'' a half-integer, for which the CPT effect is absent in a classical field. We propose an idea to use an optically thick medium with a transition $F''\to F''$ with $F'' \ge
3/2$ a half-integer as a "quantum filter", which transmits only a quantum light with limited number of photons. Such a quantum filter can be used as a deterministic source of Fock's state of light.

42.50.Gy - Effects of atomic coherence on propagation, absorption, and amplification of light; electromagnetically induced transparency and absorption.
03.67.-a - Quantum information.

© EDP Sciences 2005