Extrapolation of the intensity autocorrelation function of a quantum-dot micropillar laser into the thermal emission regime

We present investigations on the coherence of the emission from the fundamental mode of an AlGaInAs/GaAs quantum-dot microcavity laser. We measure the first-order field-correlation function g((1))(tau) with a Michelson interferometer, from which we determine coherence times of up to 20 ns for the highest pump powers. To fully characterize the coherence properties of the cavity emission, we apply a phenomenological model that connects the first-and second-order correlation functions. Hereby it is possible to overcome the limited sensitivity of the streak camera used for photon-correlation measurements, and thus to extend the accessible excitation-power range for g((2))(tau) down to the thermal regime. (C) 2011 Optical Society of America