We show that it is possible to realize simultaneous Raman lasing at two different frequencies using a double-λ system pumped by a bi-frequency field. The bi-frequency Raman lasers are phase-locked to one another, and the beat-frequency matches the energy difference between the two meta-stable ground states. Akin to a conventional Raman laser, the bi-frquency Raman lasers are expected to be subluminal. As such, these are expected to be highly stable against perturbations in cavity length, and have quantum noise limited linewidths that are far below that of a conventional laser. Because of these properties, the bi-frequency Raman lasers may find important applications in precision metrology, including atomic interferometry and magnetometry. The phase-locked Raman laser pair also represent a manifestation of lasing without inversion, albeit in a configuration that produces a pair of non-degenerate lasers simultaneoulsy. This feature may enable lasing without inversion in frequency regimes not accessible using previous techniques of lasing without inversion. To elucidate the behavior of this laser pair, we develop an analytical model that describes the stimulated Raman interaction in a double-λ system using an effective 2-level transition. The approximation is valid as long as the excited states adiabatically follow the ground states, as verified by numerical simulations. The effective model is used to identify the optimal operating conditions for the bi-frequency Raman lasing process. This model may also prove useful in other potential applications of the double-λ system, including generation of squeezed light and spatial solitons.
|Original language||English (US)|
|State||Published - Feb 24 2018|
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