Abstract
In this work we present a cavity-enhanced InAs/In_0.53Al_0.23Ga_0.24As quantum dot (QD) single-photon source in the telecom C-band with a record-low biexciton emitter decay time of \SI{67.4(2)}{ps} under resonant two-photon excitation (TPE). We observe strong multiphoton suppression associated with g⁽²⁾X(0) = 0.006(1) and g⁽²⁾XX(0) = 0.007(1) for the exciton (X) and biexciton (XX) emission, respectively. Due to a asymmetric Purcell enhancement of the XX-X cascade, the two-photon interference (TPI) visibility of XX photons under π-pulse excitation of V_TPI = 90(3)% reaches the theoretical limit and clearly exceeds the ∼60% expected for standard XX-X cascades without photonic engineering. Furthermore, adding a second timed laser pulse coinciding with XX emission energy, we demonstrate stimulated TPE in the telecom C-Band. The result is an improved TPI visibility of the X photons of V_TPI=0.69(3) compared to TPE with V_TPI=0.61(4), with both being reduced compared to the theoretical values due to present dephasing effects. The advances presented in this work hold important promises for the implementation of advanced schemes of quantum communication using deterministic quantum light sources.