Coherent Two-Photon Interactions with Atomic Sodium Vapor.

An experimental and theoretical investigation is made of the angular spectrum of a near-resonant femtosecond laser pulse propagating through sodium vapor. A directional fluorescence emission corresponding to single-photon sodium transition $3S\ensuremath{\rightarrow}3{P}_{1∕2,3∕2}$ has been registered for the pump wavelength ranging from $540\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}605\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ . It is found that such emission can be detected under the conditions of single-photon (enhanced by two-photon) resonance of pump frequency with relevant atomic states. Theoretical treatment of the field-matter interaction by means of the nonperturbative (semiclassical) approach revealed conical components of the cylindrically symmetric beam spectrum originating both from the fluorescence induced by coherent atomic polarization and four-wave mixing.An experimental and theoretical investigation is made of the angular spectrum of a near-resonant femtosecond laser pulse propagating through sodium vapor. A directional fluorescence emission corresponding to single-photon sodium transition $3S\ensuremath{\rightarrow}3{P}_{1∕2,3∕2}$ has been registered for the pump wavelength ranging from $540\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}605\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. It is found that such emission can be detected under the conditions of single-photon (enhanced by two-photon) resonance of pump frequency with relevant atomic states. Theoretical treatment of the field-matter interaction by means of the nonperturbative (semiclassical) approach revealed conical components of the cylindrically symmetric beam spectrum originating both from the fluorescence induced by coherent atomic polarization and four-wave mixing.

Physical Review AMar 16, 200714 citations

540\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}605\phantom{\rule{0.3em}{0ex}}\mathrm{nm}

. It is found that such emission can be detected under the conditions of single-photon (enhanced by two-photon) resonance of pump frequency with relevant atomic states. Theoretical treatment of the field-matter interaction by means of the nonperturbative (semiclassical) approach revealed conical components of the cylindrically symmetric beam spectrum originating both from the fluorescence induced by coherent atomic polarization and four-wave mixing.