A 256 x 256 SPAD array with in-pixel Time to Amplitude Conversion for Fluorescence Lifetime Imaging Microscopy
Luca Parmesan, Neale A. W. Dutton, Neil J. Calder, Nikola Krstajić, Andrew J. Holmes, Lindsay A. Grant, Robert K. Henderson
Abstract
A high resolution Time Correlated Single Photon Counting (TCSPC) image sensor based on sample and hold Time to Amplitude Converter (TAC) pixels and a global ramp voltage is presented. The 256 × 256 array achieves an 8 µm Pixel Pitch (PP), 19.63 % Fill Factor (FF), output voltage range (0.7 V) and time jitter of 368 ps at 10 fps employing an off-chip 14-bit differential Analogue to Digital Converter (ADC). A column-parallel flash ADCis also implemented, allowing coarse 3-bin TCSPC histogramming at 4 kfps for video rate fluorescence lifetime imaging.
Topics & Concepts
PixelJitterAmplitudeOpticsPhoton countingPhysicsImage sensorFlash (photography)Time-to-digital converterBinTime delay and integrationChipMaterials scienceAnalog-to-digital converterDetectorVoltageComputer scienceTelecommunicationsClock signalAlgorithmQuantum mechanicsAdvanced Optical Sensing TechnologiesAdvanced Fluorescence Microscopy TechniquesIntegrated Circuits and Semiconductor Failure Analysis