Non­lin­ear down-con­ver­sion in a single quantum dot

In the field of quantum dot optics, the exploitation of nonlinear processes remained so far limited to the coherent control of population and to the resonant 2-photon excitation of biexcitons. With our current work we have pioneered a new concept, which enables the control of single photon emission by a nonlinear down-conversion process. Starting from a biexciton state lB>, a tunable control laser field defines a virtual state in a stimulated process (SDC). From there, spontaneous emission to the ground state lG> leads to optically controlled single photon emission. Based on this concept, the energy and polarization of the single photon emission can be controlled in a complementary way by a classical laser field. The results lay the foundations for a new generation of nonlinear optical devices based on quantum optical principles.

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Nonlinear down-conversion in a single quantum dot

B. Jonas, D. Heinze, E. Schöll, P. Kallert, T. Langer, S. Krehs, A. Widhalm, K.D. Jöns, D. Reuter, S. Schumacher, A. Zrenner, Nature Communications (2022), 13(1), 1387

 

Excitation/down-conversion scheme for tunable single photon emission from a virtual state.