Increase of the cross section and narrowing of the line of two-photon absorption as a result of the Dicke effect
Barantsov V.I., Popov A.K.
We demonstrate the possibility of complete elimination of the uncompensated Doppler broadening in two-photon absorption. Narrowing down to the natural line width is connected with the Dicke effect and is accompanied by an abrupt increase of the absorption. The use of single-photon resonance for this purpose increases additionally the two-photon absorption cross section.