32 × 32 CMOS SPAD Imager for Gated Imaging, Photon Timing, and Photon Coincidence

Portaluppi, Davide; Conca, Enrico; Villa, Federica

doi:10.1109/jstqe.2017.2754587

Cited by 51 publications

(43 citation statements)

References 8 publications

(4 reference statements)

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“…Q-ISM is compatible with standard confocal microscopy with a few additional requirements from the experimental setup and the fluorescent markers. First, the setup requires a small array of detectors with nanosecond scale temporal resolution such as a small monolithic SPAD array or a fiber bundle detector 32,33 . The latter setup avoids inter-detector cross-talk, a crucial advantage for accurate measurement of antibunching.…”

Section: Discussionmentioning

confidence: 99%

Super-resolution enhancement by quantum image scanning microscopy

et al. 2018

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The principles of quantum optics have yielded a plethora of ideas to surpass the classical limitations of sensitivity and resolution in optical microscopy. While some ideas have been applied in proof-of-principle experiments, imaging a biological sample has remained challenging mainly due to the inherently weak signal measured and the fragility of quantum states of light. In principle, however, these quantum protocols can add new information without sacrificing the classical information and can therefore enhance the capabilities of existing super-resolution techniques. Image scanning microscopy (ISM), a recent addition to the family of super-resolution methods, generates a robust resolution enhancement without sacrificing the signal level. Here we introduce quantum image scanning microscopy (Q-ISM): combining ISM with the measurement of quantum photon correlation allows increasing the resolution of ISM up to two-fold, four times beyond the diffraction limit. We introduce the Q-ISM principle and obtain super-resolved optical images of a biological sample stained with fluorescent quantum dots using photon antibunching, a quantum effect, as a resolution enhancing contrast mechanism. Main TextThe diffraction limit, as formulated by Abbe, sets the attainable resolution in far-field optical microscopy to about half of the visible wavelength 1 , hindering its applicability in life science studies at very small scales. Over the past two decades, several super-resolution methods have successfully overcome the diffraction limit, including emission depletion microscopy, localization microscopy and structured illumination microscopy 2-6 . The continuous and rapid improvement in detector technology has enabled two more recent developments in the field of super-resolution microscopy, which are the center of this work: quantum super-resolution microscopy and image scanning microscopy (ISM). As for the first, a surge of interest in super-resolution imaging based on quantum optics concepts 7-13 , inspired and facilitated by the progress in high temporal resolution imagers, resulted in a few successful proof-of-principle demonstrations 7,8,14 . The second, ISM, relies on a small array of fast detector and offers a two-fold enhancement of resolution 15,16 . Since ISM is compatible with a standard confocal microscope architecture it has already been integrated into commercial products.While all super-resolution modalities violate at least one of the basic assumptions of the Abbe theory, many rely on breaking more than one. For instance, stimulated emission depletion (STED) and saturated structured illumination microscopy (SSIM) breach both the assumption of a linear response of a fluorophore to the excitation light and that of a uniform illumination field 17,18 . In contrast, the few demonstrations of quantum super-resolution microscopy 7,8,14 relied solely on violating the implicit assumption, underlying Abbe's derivation, that light behaves as waves rather than particles. ISM, as well, depends on violating a single assumption, a u...

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Section: Discussionmentioning

confidence: 99%

Super-resolution enhancement by quantum image scanning microscopy

et al. 2018

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“…Thus, any detection within the subgroup following this time instant will now include the absolute dead time of the SPAD, t d,spad . Under these conditions, Equations (11) and (12) are now modified to include the dead time of the SPAD as follows…”

Section: Analytical Model Of a Dtof Sensormentioning

confidence: 99%

“…Mitigating challenges from high background noise have been addressed by coincidence detection (or similar technique) on the sensor [7,11,12,16]. Coincidence detection is a well-known technique which utilizes spatio-temporal correlation of photons within a laser pulse to filter out background noise photons which are uniformly distributed in time.…”

Section: Dtof Sensor Adapted For Coincidence Detectionmentioning

confidence: 99%

“…A supporting electronic circuitry then measures the arrival time of these photons. In DTOF sensors, time-to-digital converters (TDCs) are typically used for this purpose [8,[10][11][12][13][14]. TDCs have been implemented at per-pixel level, reported in References [10,15], as well as in shared architectures [8,13].…”

Section: Introductionmentioning

confidence: 99%

“…At the sensor-level, ambient light suppression has been addressed by coincidence detection on chip [11,12,16], a well-known technique utilizing spatio-temporal closeness of photons within a laser pulse to filter out background noise photons. While TCSPC with coincidence detection have shown effective noise-filtering properties, imaging in a wide dynamic range scenario is an ongoing challenge.…”

Section: Introductionmentioning

confidence: 99%

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Modeling and Analysis of a Direct Time-of-Flight Sensor Architecture for LiDAR Applications

Zhang

Charbon

2019

Sensors

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Tel.: +41-216-954-413 † This paper is an extended version of our paper published in: Padmanabhan, P.; Zhang, C.; Charbon, E.Analysis of a modular SPAD-based direct time-of-flight depth sensor architecture for wide dynamic range scenes in a LiDAR system. Abstract:Direct time-of-flight (DTOF) is a prominent depth sensing method in light detection and ranging (LiDAR) applications. Single-photon avalanche diode (SPAD) arrays integrated in DTOF sensors have demonstrated excellent ranging and 3D imaging capabilities, making them promising candidates for LiDARs. However, high background noise due to solar exposure limits their performance and degrades the signal-to-background noise ratio (SBR). Noise-filtering techniques based on coincidence detection and time-gating have been implemented to mitigate this challenge but 3D imaging of a wide dynamic range scene is an ongoing issue. In this paper, we propose a coincidence-based DTOF sensor architecture to address the aforementioned challenges. The architecture is analyzed using a probabilistic model and simulation. A flash LiDAR setup is simulated with typical operating conditions of a wide angle field-of-view (FOV = 40 • ) in a 50 klux ambient light assumption. Single-point ranging simulations are obtained for distances up to 150 m using the DTOF model. An activity-dependent coincidence is proposed as a way to improve imaging of wide dynamic range targets. An example scene with targets ranging between 8-60% reflectivity is used to simulate the proposed method. The model predicts that a single threshold cannot yield an accurate reconstruction and a higher (lower) reflective target requires a higher (lower) coincidence threshold. Further, a pixel-clustering scheme is introduced, capable of providing multiple simultaneous timing information as a means to enhance throughput and reduce timing uncertainty. Example scenes are reconstructed to distinguish up to 4 distinct target peaks simulated with a resolution of 500 ps. Alternatively, a time-gating mode is simulated where in the DTOF sensor performs target-selective ranging. Simulation results show reconstruction of a 10% reflective target at 20 m in the presence of a retro-reflective equivalent with a 60% reflectivity at 5 m within the same FOV.

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Single Photon Avalanche Diode Arrays for Quantum Imaging and Microscopy

et al. 2021

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Quantum imaging and microscopy profit from quantum correlations and entanglement to image objects and samples with resolution and sensitivity that goes far beyond what can be achieved through classical optics. In order to carry out these techniques, suitable detectors with specific features must be employed. This paper aims to highlight the importance of sensors based on single photon avalanche diodes (SPAD) in quantum imaging and microscopy applications, paving the way for the next-generation ideal quantum imager. After reviewing the main techniques (based on quantum physics principles) for improving the resolution and sensitivity of a sample image, the pros and cons of different sensors, such as avalanche photodiodes (APDs), and the intensified and electron-multiplying charge coupled devices (ICCDs and EMCCDs), are identified. Then the analysis mainly focuses on SPAD-based detectors, identified as the best candidates for quantum imaging, critically discussing the requirements and performance, also in relation to already existing SPAD-based architectures with specific features fitting the application. Eventually, next-generation quantum imagers should integrate together all the best architectural choices herewith presented, so as to detect photon coincidences and to perform efficient event-driven readout, also by exploiting a suitable technology and SPAD design to optimize the discussed detection performance.

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32 × 32 CMOS SPAD Imager for Gated Imaging, Photon Timing, and Photon Coincidence

Cited by 51 publications

References 8 publications

Super-resolution enhancement by quantum image scanning microscopy

Super-resolution enhancement by quantum image scanning microscopy

Modeling and Analysis of a Direct Time-of-Flight Sensor Architecture for LiDAR Applications

Single Photon Avalanche Diode Arrays for Quantum Imaging and Microscopy

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