Dicke coherent narrowing in two-photon and Raman spectroscopy of thin vapor cells
G. Dutier, Petko Todorov, I. Hamdi +4 more
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.
arXiv:physics/0506025•Physical Review A•Oct 14, 2005•4 citations