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

Abstract

We continue our previous program where we introduced a set of quantum-based design rules directed at quantum engineers who design single-photon quantum communications and quantum imaging devices. Here, we report on experimental progress using SPAD (single photon avalanche diode) arrays of our design and fabricated in CMOS (complementary metal oxide semiconductor) technology. Emerging high-resolution imaging techniques based on SPAD arrays have proven useful in a variety of disciplines including bio-fluorescence microscopy and 3D vision systems. They have also been particularly successful for intra-chip optical communications implemented entirely in CMOS technology. More importantly for our purposes, 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, several million times per second, due to a very short detection cycle. The tiny chip area means they are suitable for highly miniaturized quantum imaging devices and that is how we employ them in this paper. Our quantum path integral analysis of the Young-Afshar-Wheeler interferometer showed that Bohr's complementarity principle was not violated due the previously overlooked effect of photon bifurcation within the lens-a phenomenon consistent with our quantum design rules-which accounts for the loss of which-path information in the presence of interference. In this paper, we report on our progress toward the construction of quantitative design rules as well as some proposed tests for quantum imaging devices using entangled photon sources with our SPAD imager. * Internal Accession Date Only

Photonic information processing needs quantum design rules

“…2,3 The most common method for producing entangled 'biphotons' pumps a nonlinear crystal, such as beta-barium borate (BBO), with UV photons to create photon pairs whose total momenta and energy equal that of each pump photon. An entangled pair acts like the two-segment QPI amplitude shown in Figure 2.…”

“…Under this formalism, a photon propagating in free space is represented by an infinite set of QPI amplitudes φ i between source s and detector d. The probability for detecting a physical photon is determined by summing over all of these paths, and then taking the squared modulus of the result. Some eight quantum rules 2,3 of this type will correctly calculate probabilities in VLSI informationprocessing devices. For example, in Figure 2, which shows a scat- tering event E, path φ 1 would be computed as the product of the two legs, φ 1a and φ 1b , an example of the 'AND-ing' rule.…”