Conference 11771 > Paper 11771-8
Paper 11771-8

Design of a 24×24 SPAD imager for multi-photon coincidence-detection in super resolution microscopy

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.

Presenter

Francesca Madonini
Politecnico di Milano (Italy)
Francesca Madonini was born in Crema, Italy, in 1995. She received her Bachelor degree in Biomedical Engineering and her Master degree in Electronics Engineering, both cum laude, at Politecnico di Milano in 2017 and 2019, respectively. She was double degree awarded at Politecnico di Torino, as a part of the Alta Scuola Politecnica program. Since November 2019, she is enrolled in the Research Doctorate in Information Technology (area Electronics) at Politecnico di Milano. Her current research focuses on Single Photon Avalanche Diode (SPAD) imagers for photon counting and photon timing for 2D and 3D imaging, under the supervision of prof. Federica Villa and prof. Franco Zappa. In particular, her main task consists in the design of microelectronic circuits for SPAD arrays, specifically tailored for photon coincidences measurements in the field of quantum-enhanced microscopy.
Presenter/Author
Francesca Madonini
Politecnico di Milano (Italy)
Author
Politecnico di Milano (Italy)
Author
Politecnico di Milano (Italy)
Author
Enrico Conca
Politecnico di Milano (Italy)
Author
Politecnico di Milano (Italy)