Optoelectronic devices for single photon generation (Invited Paper)

Abstract

We review progress in realizing a semiconductor source of single photons and photon pairs based on the emission of individual self-assembled quantum dots. Integration of the quantum dot into a pillar microcavity produces a strong Purcell enhancement of the radiative recombination rate, resulting in photon collection efficiencies into a lens of ~10%. The residual multi-photon emission is found to derive from the emission of other layers within the structure, such that under resonant laser excitation of the dot a greater than 50-fold reduction in the 2-photon rate can be achieved compared to a laser of the same average intensity. The polarization of the emitted photons can be controlled and selected in appropriately designed cavities. Through careful control of the dot growth conditions, we realize a single photon source at the fiber compatible wavelength of 1300nm. This is achieved by utilizing a second critical InAs coverage to produce a low density of large, long wavelength InAs quantum dots. We demonstrate also an electrically driven planar cavity structure with photon collection efficiencies into a lens of ~5%, corresponding to an order of magnitude enhancement in the photon collection compared to dots in a bulk semiconductor LED. Single photon emission is demonstrated for both the biexciton and exciton state of the quantum dot.