Broadband generation in a Raman crystal driven by a pair of time-delayed linearly chirped pulses

A pair of time-delayed linearly chirped pulses with sub-picosecond duration is used to selectively excite Raman transitions in a lead tungstate crystal. Significant molecular coherence leads to generation of up to 40 anti-Stokes and 5 Stokes sidebands. High conversion efficiency (from the two pump beams to the sidebands) is measured. The broadband generation with chirped pulses whose duration is comparable to the Raman coherence lifetime is considerably more efficient, when compared to the case of excitation by two-color femtosecond pulses. In the future, mutual coherence among the generated sidebands may allow ultrashort pulse synthesis. IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

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