Theory of mode-locking with a coherent absorber

V. V. Kozlov

В. В. Козлов, Evald E. Fradkin

Vladimir P. Kalosha, Michael Müller, J. Herrmann

HE Long-qing

A quantum theory for pulse-train from the mode-looked laser has been developed. In the theory the author uses superposition model, i. e. the atomic states are coherent after absorbed photons from different modes of a mode-locked laser. So the final atomic state should be coherently added. The resolvent operator and projector operation are used to derive the operator U. Considering the phase relationship between the modes, the light field are described by multi-mode coherent state. This method can be used to describe the resonant multi-photon processes that the pulse train from the mode locked laser interacting with atoms.

Murray Sargent

Mikhail V. Arkhipov, Rostislav M. Arkhipov, A. A. Shimko +2 more

The regime of passive mode locking in a Ti:sapphire laser with a coherent absorber resulting in the emission of pulses with a duration considerably shorter than the absorber relaxation times is demonstrated experimentally. A cell filled with rubidium vapor placed in the laser cavity serves as a coherent absorber. Mode locking arises when the laser oscillation frequency is tuned to the resonance transitions in rubidium. In our opinion, 2π pulses of self-induced transparency appear in the cavity, and the reported results represent the first experimental demonstration of passive mode locking caused by the effect of self-induced transparency, which has previously been discussed only theoretically.