Induced transparency in resonant induced Raman scattering

Heinz Steudel

T. Takagahara

Vincent Wong, Ryan S. Bennink, Alberto M. Marino +3 more

We study how coherent Stokes and anti-Stokes Raman scattering influence coherent population trapping. In an experiment using an atomic sodium vapor cell we observe induced transparency, induced absorption, and gain features, all of subnatural linewidth. The electromagnetically induced resonance is a peak or a dip depending on which side of the optical transition the fields are tuned to, and thus whether coherent anti-Stokes Raman scattering or coherent Stokes Raman scattering is the dominant process.

Li Gong, Haifeng Wang

We theoretically investigate a scheme in which stimulated Raman scattering (SRS) can be suppressed by coherently controlling the coupling between molecular states. In conventional SRS, two laser beams at different frequencies interact resonantly with molecular vibration to induce a gain and a loss for the two beams, respectively. In our scheme, a third beam is introduced to couple the vibrational state to another coupling state. As a result, SRS is suppressed in a way analogous to electromagnetically induced transparency. We calculated the SRS signal analytically by the density matrix approach, and investigated the feasibility of this scheme for real molecular imaging. In SRS microscopy, a donut-shaped coupling laser can be used to suppress the SRS signal from the rim part of the focal spot, leading to super-resolution. Based on our numerical studies, the lateral resolution starts to be enhanced when the coupling laser intensity exceeds $0.1\phantom{\rule{0.16em}{0ex}}\mathrm{TW}/\mathrm{c}{\mathrm{m}}^{2}$ at picosecond pulse duration.

Andrij M. Shvaika, O. Vorobyov, James K. Freericks +1 more

Jian Liang, M. Katsuragawa, Fam Le Kien +1 more

Summary form only given. There has been increasing interest in optical processes using strong-coupling and induced transparency, termed electromagnetically induced transparency (EIT). Although the idea of EIT started for resonant /spl and/h-scheme (Raman scheme), the idea has now been extended to far-off resonance Raman system. We have reported the spontaneous evolution of strong-coupling through stimulated Raman scattering (SRS) using solid hydrogen. In the present work, we extend the strong-coupling SRS to a more general parametric Raman sideband generation. We show using solid hydrogen as a test medium that, in tile far-off resonance Raman scheme, the strongly-coupled Raman coherence can beat with very broad-band laser radiation and can efficiently copy the broadband nature to Raman sidebands without restriction of the phase-matching, and that this efficient copying occurs on the negative Raman detuning for which the strongly-coupled eigenstate evolves to the anti-phased state (dark state).