Design rules for quantum imaging devices: experimental progress using CMOS single-photon detectors

Abstract

ABSTRACT We continue our previous program 1 where we introduced a set of quantum-based design rules directed at quantum engi-neers who design single-photon quantum communications and quantum imaging devices. Here, we report on experimentalprogress using SPAD (single photon avalanche diode) arrays of our design and fabricated in CMOS (complementary metaloxidesemiconductor)technology. Emerginghigh-resolutionimagingtechniquesbasedonSPADarrayshaveprovenusefulin a variety of disciplines including bio- uorescence microscopy and 3D vision systems. They have also been particularlysuccessful for intra-chip optical communications implemented entirely in CMOS technology. More importantly for ourpurposes, a very low dark count allows SPADs to detect rare photon events with a high dynamic range and high signal-to-noise ratio. Our CMOS SPADs support multi-channel detection of photon arrivals with picosecond accuracy, severalmillion times per second, due to a very short detection cycle. The tiny chip area means they are suitable for highly minia-turized quantum imaging devices and that is how we employ them in this paper. Our quantum path integral analysis of theYoung-Afshar-Wheeler interferometer showed that Bohr’s complementarity principle was not violated due the previouslyoverlooked effect of photon bifurcation within the lens—a phenomenon consistent with our quantum design rules—whichaccounts for the loss of which-path information in the presence of interference. In this paper, we report on our progresstoward the construction of quantitative design rules as well as some proposed tests for quantum imaging devices usingentangled photon sources with our SPAD imager.Keywords: CMOS, detector arrays, interferometer, phase twinning, quantum imaging, SPAD (single photon avalanchediode)