The mixing of Raman and laser frequencies

K. Kubota

Aurélien Benoît, Benoît Beaudou, Benoît Debord +2 more

We propose and demonstrate parametric four-wave mixing in a Raman active gas. Two lasers with a 1.7 THz frequency-difference in a strongly-driven Raman rotational-transition of D2 generate sidebands with frequency-spacing equal to the lasers frequency-difference.

G.Ya. Lyubarskii

Jingyun Fan, Alan L. Migdall

On coupling two phase-coherent frequency-conjugate laser pulses into a microstructure fiber, we observe phase-sensitive photon generation via four-wave mixing, and suppression of Raman emission at the middle frequency.

Martin P. van Exter, Ad Lagendijk

Panming Fu, Zuhe Yu, Xin Mi +2 more

We have studied theoretically the dependence of the Raman-enhanced nondegenerate four-wave-mixing (RENFWM) spectrum on the relative time delay between two pump beams \ensuremath{\tau} when a thermal effect exists in the sample. Using the chaotic model for the incident laser beams, we give the conditions that the thermal background can be eliminated completely when the relative time delay is much longer than the laser coherence time. In this limit, the theoretical RENFWM spectra show the normal asymmetry due to the interference between the Raman-resonant term and the nonresonant background originating solely from the molecular-reorientational grating. We then turn our attention to the dependence of the RENFWM signal intensity on the relative time delay when the laser frequencies are fixed. Our results indicate that RENFWM is asymmetric about \ensuremath{\tau}=0 and the maximum of the RENFWM signal does not occur at \ensuremath{\tau}=0. When the beating frequency between the pump beam and the probe beam is off resonant from the Raman mode, the RENFWM signal exhibits damping oscillation as the time delay increases. We also show that the temporal behavior of the RENFWM signal is drastically different if the laser sources are described by a phase-diffusion model. The different roles of the phase fluctuation and the amplitude fluctuation can be understood in the time domain.