Noisy detectors with unmatched detection efficiency thwart identification of single photon emitters via photon coincidence correlation

Single photon emitters (SPEs) are often identified with a Hanbury Brown and Twiss intensity interferometer (HBTII) consisting of a 50:50 beamsplitter and two time-correlated single photon counters. For an SPE, the cross-correlation of photon arrival time between the two detectors, $g^{(2)}(\tau)$, shows a hallmark dip to zero at $\tau=0$. One common heuristic for identifying SPEs is by measuring a system to have $g^{(2)}(0)<1/2$. Here in, we use stochastic methods to simulate the case of a SPE observed with non-ideal detectors and optics. We show that identification of SPEs is thwarted when the detectors have asymmetric detection efficiency, and when detector background noise is more than half the true SPE signal rate.