Vacuum-mediated multiphoton transitions
نویسندگان
چکیده
We have measured the emission spectra of two-level-like atoms driven by a spatially inhomogeneous bichromatic field comprised of one resonant and one off-resonant component. Under these excitation conditions, observed spectra consist of several narrow peaks appearing on top of a broad continuumlike structure. This experimental approach provides for selective observation of those spectral features having a Rabifrequency-independent emission frequency. Such emission processes involve multiphoton transitions, with one leg being spontaneous, between dressed-state levels differing only in their photonic quantum numbers; i.e., between equivalent dressed-state-doublet sublevels. Related vacuum-mediated transitions have recently been invoked as an underlying mechanism of inversionless gain.
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