arXiv:physics/0506025 · Physical Review A
Dicke coherent narrowing in two-photon and Raman spectroscopy of thin vapor cells
G. Dutier, Petko Todorov, I. Hamdi, Isabelle Maurin, Solomon M. Saltiel, Daniel Bloch, M. Ducloy
Abstract
The principle of coherent Dicke narrowing in a thin vapor cell, in which sub-Doppler spectral line shapes are observed under a normal irradiation for a $\ensuremath{\lambda}∕2$ thickness, is generalized to two-photon spectroscopy. Only the sum of the two wave vectors must be normal to the cell, making the two-photon scheme highly versatile. A comparison is provided between the Dicke narrowing with copropagating fields, and the residual Doppler broadening occurring with counterpropagating geometries. The experimental feasibility is discussed on the basis of a first observation of a two-photon resonance in a 300-nm-thick Cs cell. Extension to the Raman situation is finally considered.