  An engineering technique using continuous quantum measurement together with a
change detection algorithm is proposed to improve the probability of single
photon emission for a quantum-dot based single-photon source. The technique
involves continuous monitoring of the emitter, integrating the measured signal,
and a simple change detection circuit to decide when to stop pumping. The idea
is to pump just long enough such that the emitter $+$ cavity system is in a
state that can emit at most one photon with high probability. Continuous
monitoring provides partial information on the state of the emitter. This
technique is useful when the system is operating in the weak coupling regime,
and the rate of pumping is smaller than, or comparable to, the emitter-cavity
coupling strength, as can be the case for electrical pumping.
