A coherent Raman oscillator pumped by a frequency comb

Research focuses on producing coherent Raman oscillation in di-atomic Alkali dimers (Li2, K2, Rb2) gas, by placing the gas in a matched optical cavity, and pumped by a matched frequency comb." As opposed to parametric oscillations and standard lasers, the crossing lasing threshold is possible due to coherent dynamics of the excited vibrational wave packet induced by the pump. Whereas in lasers, the pump is essentially incoherent, and in parametric oscillators, the coherence originates in the pump itself, and this signature is imprinted in the emitted signal/idler fields.

here, the coherence is due to the wave packet dynamics, and the signature is of this dynamics, and not of the pump. We show how a train of pulses emerges which follow the vibrational dynamics of the excited potential surfaces, and if not too far above threshold, can stimulate transitions to a single pure non-zero vibrational state in the ground potential. (Paper)




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