We improve the performance of temporal coincidence counting using fractional Fourier domain time-frequency correlations achieved through non-local dispersion protocols. This protocol achieved up to an 89 dB improved detection rate using receiver operating characteristics.
Quantum enhanced optical target detection provides a unique route to increased noise resilience of classical LiDARs (laser imaging, detection, and ranging) by using time correlation of non-classical photon pairs. Such enhancement is dictated by the detector temporal uncertainty that is typically orders of magnitude larger than the intrinsic correlation time. To circumvent such detector limitation, we explore the possibility of measuring correlation in the fractional-order Fourier domain (FrFD), which can be realized with the non-local dispersion cancellation. Experimentally, we verify this principle using a fiber-coupled waveguide source of photon pairs, showing enhanced noise rejection as compared with conventional time-domain coincidence detection and classical intensity detection. For false alarm rates of 10 −9 , an 89 dB improved detection rate is measured using receiver operating characteristics when comparing our FrFD protocol with classical intensity detection. Additionally, we discussed the resilience of FrFD correlation against intentionally prepared counterfeit signal photons. The possibility enabled by measuring correlation in the FrFD should also provide potential benefit for various sensing and communication protocols that relies on coincidence detection.
Entangled photon target detection provides a unique route to increase the noise resilience of classical LiDAR technologies by incorporating the use of probe-reference coincidence counting. One of the factors that determine the performance of these systems is the hardware temporal resolution. This is due to the noise detected within the detector time constants. To outperform this limitation, we use non-local dispersion compensation to spread noise outside of the detection window while maintaining the probe-reference coincidences. In this paper, we predict and experimentally characterize the dependence of a non-local target detection protocol on detection time, transmission, source power, and background noise by use of receiver operating characteristics (ROC). Two periodically poled Lithium Niobate crystals (PPLN) are used to create a high flux free space target detection setup. Advantages of up to 32dB noise rejection are seen with detection times below 5ms. The performance modeling is applicable to different source inputs, allowing future design and creation of large scale sensing technologies that surpass classical detection limits.