Design of a 24×24 SPAD imager for multi-photon coincidence-detection in super resolution microscopy
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2021-04-14 |
| Authors | Francesca Madonini, Fabio Severini, Alfonso Incoronato, Enrico Conca, Federica Villa |
| Institutions | Politecnico di Milano |
| Citations | 7 |
Abstract
Section titled “Abstract”Microscopy resolution below the diffraction limit can be achieved by exploiting quantum light properties. NitrogenVacancy (NV) color centers in diamond, dye molecules and quantum dots are examples of single-photon emitters, whose antibunching property allows super-resolution imaging through the measurement of high-order autocorrelation functions. In this work, we present a novel Single Photon Avalanche Diode (SPAD) array architecture optimized for n-fold photon coincidence counting, in each point across the whole sensitive area. It is implemented in a 160 nm Bipolar-CMOS-DMOS (BCD) technology, and it includes 24 × 24 SPAD pixels with 50-μm pixel pitch and 10-μm SPAD diameter. Multi-photon coincidences (within time windows ranging from 2 ns to 500 ns) are identified by post-processing of the in-pixel timing data. Given the expected low photon rate on the detector in quantum imaging applications, on-chip logic discards unwanted information to limit readout throughput and data storage. In fact, reading the whole array would take 3 μs, while skipping rows detecting no photon reduces the readout time to 240 ns in case of no photon detected over the entire array. Moreover, we implemented a multi-gate approach, which avoids halting the array during readout, thus enabling multiple data acquisitions. Thanks to these power-saving expedients and efficient readout, the architecture is scalable towards multiple modules, such as 48 × 48 or 96 × 96-pixel arrays. Finally, it features the possibility of being coupled with a micro-lens array to reach a 78% equivalent fill-factor.
Tech Support
Section titled “Tech Support”Original Source
Section titled “Original Source”References
Section titled “References”- 2014 - A Fully Digital 8x16 SiPM Array for PET Applications With Per-Pixel TDCs and Real-Time Energy Output
- 2018 - A 32x32-pixel time-resolved single-photon image sensor with 44.64 pm pitch and 19.48% fill-factor with on-chip row/frame skipping features reaching 800 kHz observation rate for quantum physics applications [Crossref]
- 2014 - CMOS SPADs with up to 500 pm diameter and 55% detection efficiency at 420 nm
- 2018 - Single-Photon Avalanche Diodes in a 0.16 pm BCD Technology With Sharp Timing Response and Red-Enhanced Sensitivity