Correction for the detector-dead-time effect on the second-order correlation of stationary sub-Poissonian light in a two-detector configuration

Abstract

Exact measurement of the second-order correlation function g (2) (t) of a light source is essential when investigating the photon statistics and the light generation process of the source. For a stationary single-mode light source, Mandel Q factor is directly related to g (2) (0). For a large mean photon number in the mode, the deviation of g (2) (0) from unity is so small that even a tiny error in measuring g (2) (0) would result in an inaccurate Mandel Q. In this work, we have found that detector dead time can induce a serious error in g (2) (0) and thus in Mandel Q in those cases even in a two-detector configuration. Our finding contradicts the conventional understanding that detector dead time would not affect g (2) (t) in two-detector configurations. Utilizing the cavity-QED microlaser, a well-established sub-Poissonian light source, we measured g (2) (0) with two different types of photodetectors with different dead time. We also introduced prolonged dead time by intentionally deleting the photodetection events following a preceding one within a specified time interval. We found that the observed Q of the cavity-QED microlaser was underestimated by 19% with respect to the dead-time-free Q when its mean photon number was about 600. We derived an analytic formula which well explains the behavior of the g (2) (0) as a function of the dead time.

Indirect measurement of three-photon correlation in nonclassical light sources

“…Mean photon number in the cavity was roughly 600. dead time measured in the regime of sub-Poisson photon statistics of the cavity-QED microlaser. A similar plot appeared in our previous work [15]. The red square is obtained by the experiment when the mean photon number of the cavity-QED microlaser is approximately 600.…”

“…We simulated the prolonged dead times, corresponding to the black circles, in the same way as in Ref. [15]. The prolonged dead times imposed on both detectors were the same.…”

“…In the usual N -detector configuration for N thorder correlation measurement, signal-to-noise ratio (SNR) is given by (T 0 /τ w ) N /(T 0 /t b ) N −1 = (T 0 /τ w )(t b /τ w ) N −1 [15], where t b is the bin time used in the calculation of the N -th order correlation function and T 0 is the total measurement time. The bin time t b should be small enough to resolve the temporal dependence of the correlation function, and thus it typically satisfies t b τ w .…”

Preparation of a nonlinear coherent state of the mechanical resonator in an optomechanical microcavity

“…The SOCF g (2) (0) can be applied to distinguish whether the statistical properties of the field is super-Poissonian (g (2) (0) > 1), Poissonian (g (2) (0) = 1), or sub-Poissonian (g (2) (0) < 1). The sub-Poissonian statistics is usually correlated to non-classical state [81,82]. In order to get the insight into the non-classical properties of the phonon, we numerically calculate the SOCF in the Fock state representation with the following expression…”

Observation of scalable sub-Poissonian-field lasing in a microlaser

“…The deadtime effect from intrinsic detector characteristics can be corrected by the methodology introduced in Ref. [40]. In order to calibrate the mean atom number N and the mean photon number n in the cavity mode, we measured the fluorescence of the intracavity atoms at 1 S 0 ↔ 1 P 1 transition (λ = 553nm) and the microlaser output photon flux simultaneously as the atomic beam flux was increased.…”