Quantum Dot Emission Confined by a Spherical Photonic Dot

The concept of a fully three-dimensional photonic dot is realized in glass microspheres with CdSe quantum dots (QDs) incorporated. The steady-state and time-resolved photoluminescence of QDs is studied with and without coupling to the photonic dot states. It has been found that the radiative lifetime of a single quantum dot is controlled by the photon lifetime of high-Q cavity modes. At T = 20 K, the increase in the radiative recombination rate is demonstrated and Purcell factors between 2 and 5 are measured. Under pulsed ns-excitation, room-temperature lasing in a single photonic dot is achieved.