Abstract

In this paper we present a novel single-photon detector specifically designed for Non-Line-Of-Sight (NLOS) imaging applications within the framework of the DARPA REVEAL program. The instrument is based on a linear 16 × 1 Complementary Metal-Oxide-Semiconductor (CMOS) Single-Photon Avalanche Diode (SPAD) array operated in fast-gated mode by a novel fast-gating Active Quenching Circuit (AQC) array, which enables the detectors with sub-ns transitions thanks to a SPAD-dummy approach. The detector exhibits a timing resolution better than 50 ps (Full Width at Half Maximum - FWHM) at a measurement repetition rate up to 40 MHz, and provides 16 independent outputs compatible with commercial Time-Correlated Single-Photon Counting (TCSPC) instrumentation. The instrument has been experimentally characterized and operated in preliminary NLOS imaging acquisitions where a 40 × 60 cm hidden object is successfully reconstructed by scanning over a grid of 150 × 150 positions.

Highlights

  • We present the design of a complete single-photon detector based on a novel 1D array of Complementary Metal-Oxide-Semiconductor (CMOS) Single-Photon Avalanche Diodes (SPADs) driven by an array of Active Quenching Circuits (AQCs) in fast-gated regime, developed within the framework of the DARPA REVEAL

  • The newly developed fast-gating AQC is based on the architecture of the SPAD driver and quenching circuit presented in [29], featuring few minor modifications mainly tailored to reduce the overall number of external connections of the chip, allowing to design an array structure

  • We presented a novel single-photon detector based on a 16 × 1 CMOS SPAD array

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Summary

Introduction

Optimal performance achieved throughout previous years by fast-gated SPAD detectors has fostered their diffusion in a wide range of different applications, from fluorescence lifetime measurements to time-resolved Near-InfraRed Spectroscopy (NIRS), quantum cryptography and. Fast-gated single-photon detectors adopted in TOF measurements may allow to recover information on objects hidden from the direct Line-Of-Sight (LOS) of the imaging system, thanks to the acquisition of photons after multiple reflections through the scene, implementing the so-called. NLOS imaging techniques and systems gained interest as they enable the remote viewing of hidden scenarios dangerous or difficult to access, as NLOS imaging may be adopted in rescuing scenarios or hazardous industrial environments, in the clinical field to improve endoscopic analysis and surgeries and lastly in security and automotive applications All these scenarios require different operating parameters in terms of reconstruction volume (from a few cm for endoscopic analysis up to tens of m3 for room reconstructions) and light intensity, a NLOS imaging system should offer great flexibility and reconfigurability in order to satisfy different application areas. The system features 16 independent SPADs with the possibility to increase the number of detectors up to 64 pixels, still guaranteeing a time-gated operation with OFF/ON transitions < 1 ns, and an overall Single-Photon Timing Resolution (SPTR) lower than 50 ps (FWHM)

Non-Line-of-Sight Imaging
NLOS Systems and Reconstruction Techniques
Improvements in NLOS Reconstruction
Instrument Design
Fast-Gating AQC Array
50 Ω impedance andanthus an external buffer is
System
Chip-Carrier Board
A Negative
Control
Fast-Gating AQC Array–Design Issues
Optical Crosstalk
Electroluminescence
Detection Linearity in Gated Operation
Single-Photon
40 MHz response to a aa 113 nm when operated withwith a 6 ns
Results reported in Table
NLOS Preliminary Measurement
11. Photon
Conclusions
Full Text
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