Restraint Can Be a Turn On

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Science  13 Apr 2001:
Vol. 292, Issue 5515, pp. 171
DOI: 10.1126/science.292.5515.171c

The excitation and relaxation of carriers between the discrete energy levels of a quantum dot result in the absorption and emission, respectively, of light at discrete wavelengths. The ability to control and harness such spontaneous processes would provide many applications in optoelectronics, but doing so directly is difficult and has necessitated indirect approaches to the problem. Bayer et al. placed a quantum dot in a structured optical microcavity: a box in which the optical modes are confined. They found that matching the optical modes of the microcavity to those of the quantum dot led to an enhancement of the emission rate from the dot, thereby switching the dot on. When the photon modes of the microcavity and the quantum dot are off-resonance, the emission rate is suppressed, and the dot is switched off. — ISO

Phys. Rev. Lett.86, 3168 (2001).

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