Triggered Single‐Photon Emission of Resonantly Excited Quantum Dots Grown on (111)B GaAs Substrate

Abstract

In the recent decades, semiconductor quantum dots (QDs) have proven to be valuable candidates as sources for various photonic applications. Of particular interest are, due to their wide‐ranging applicability in quantum communication and computation, indistinguishable photons as well as entangled photon pairs, which can be emitted on demand. The latter require highly symmetric QDs with a small to vanishing excitonic fine‐structure splitting. Herein, quantum optical properties of QDs grown via molecular‐beam epitaxy (MBE) on (111)B‐GaAs substrate are reported to study their emission in terms of triggered single‐photon emission under quasi‐resonant p‐shell excitation, and under strict resonant s‐shell excitation. The investigations reveal very good emission properties of these types of QDs, especially under s‐shell resonant excitation. In fact, the results yield almost background‐free triggered single photons with excellent multiphoton suppression associated with g(2)(0) = (0.033 ± 0.027) and a degree of indistinguishability of (41 ± 10)%. The achieved results underline the high optical quality of (111)‐QDs and show their high potential for applications in photonic quantum technologies.