High-speed Photon-Number-Resolution Quanta Imaging Sensor Array

Single-photon counting and timing achieves light detection at the fundamental quantum limit, unlocking next generation capabilities in quantum imaging and environmental sensing. Many applications require counting/timing photons at very high rates (>GHz), leading to instantaneous photon bunching (“pileup”) that causes photons to be missed. The result is data loss, degraded statistics and nonlinearities. Current detectors mitigate such deluges by breaking the flow of photons onto arrays of many small pixels, thereby reducing the count rate for each individual pixel and enabling reliable counting even for very impulsive signals. They also group counts into macropixels and time-bins to reduce analog-to-digital conversion limitations and off-chip data transfer bandwidth requirements. However, quantum imaging often looks at time correlations between pairs of photons on femtosecond to picosecond time scales, which register as a single click on a Geiger detector. Photon Number Resolution (PNR) can enable measurement of simultaneous incident photons to provide insight into quantum and statistical properties of light.[1] Scalable Superconducting Nanowire Single-Photon Detectors (SNSPDs) with PNR provide near ideal performance, but will not be considered for this topic due to cryogenic temperature operation. Quanta Imaging Sensors (QIS) with jots or other CMOS compatible fabrication have demonstrated PNR at room temperature by achieving ultra-low read noise.[2],[3],[4] A variety of physical processes have demonstrated GHz count rates,[5],[6],[7],[8],[9] and novel circuits have also been developed to advance single-photon detection technologies such as spiking neural network (SNN) neuromorphic readout integrated circuits (ROICs).[10],[11],[12] The camera architecture must support time-of-flight (ToF) or equivalent depth-ranging modalities, and should be compatible with entangled or correlated photon sources. This topic seeks an ultimate PNR sensor with the following performance: Pixel-Level Performance: • Photon Counting Rate: ≥120 MHz per pixel • Photon Number Resolution ≥16 • External Quantum Efficiency (EQE): ≥60% between 450 – 550 nm, including fill factor losses Array & Architecture Scalability: • Array Size: Scalable up to Megapixels • Monochromatic Readout & On-Chip Processing: • Frame Rate: ≥120 MHz operating in 10 µs duration bursts at up to a 16 kHz repetition rate (i.e. ≥1200 frames in 10 µs, repeated every 62.5 µs). • Hardware-Level Compression: On-chip accumulation must be able to support the summing of up to a minimum of 500 burst sequences prior to readout, enabling significant compression of raw data volume without sacrificing the frame-to-frame temporal resolution. Operating temperature between -40 °C to +45 °C Overall, the photon capacity of the sensor should be able to process bursts of ≥1016 photons per second; for example, 200 MHz x 32 PNR x 2 MPixels. Simultaneously, the sensor should have a dark count rate low enough to be able to capture signals as weak as 108 photons per second across the array, with high fidelity. Initial proposals for this topic should document current state-of-the-art commercial single-photon detector performance for the listed parameters, identify the physical factors limiting current performance, propose developing new detection mechanisms and/or circuit architectures that could exceed current limitations to meet the requirements, and identify the challenges in implementing the proposed solution. The proposer should make a convincing case that the design is scalable.