Thresholdless coherent light scattering from subband polaritons in a strongly coupled microcavity
Author(s)Williams, Benjamin S.; Hu, Qing; Gambari, Johannes; Fernandez-Dominguez, Antonio I.; Maier, Stefan A.; Kumar, Sushil; Reno, John L.; Phillips, Chris C.; ... Show more Show less
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We study a “strongly coupled” (SC) polariton system formed between the atomlike intersubband transitions in a semiconductor nanostructure and the terahertz optical modes that are localized at the edges of a gold aperture. The polaritons can be excited optically, by incoherent excitation with band-gap radiation, and we find that they also coherently scatter the same input laser, to give strikingly sharp “sideband” (SB) spectral peaks, in the backscattered spectrum. The SB intensity is a sensitive track of the polariton density and they can be detected down to a quantum noise floor that is more than 2500 times lower than the excitation thresholds of comparable quantum cascade laser diodes. Compared with other coherent scattering mechanisms, higher-order SB scattering events are readily observable, and we speculate that if suitably optimized, the effect may find utility in a passive component capable of all-optical wavelength shifting for telecommunications systems.
DepartmentMassachusetts Institute of Technology. Department of Electrical Engineering and Computer Science; Massachusetts Institute of Technology. Research Laboratory of Electronics
Physical Review B
American Physical Society
Gambari, Johannes et al. “Thresholdless coherent light scattering from subband polaritons in a strongly coupled microcavity.” Physical Review B 82.12 (2010): 121303. © 2010 The American Physical Society.
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