A 512 x 512 SPAD Image Sensor With Integrated Gating for Widefield FLIM
A 512 x 512 SPAD Image Sensor With Integrated Gating for Widefield FLIM
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DOI：
10.1109/jstqe.2018.2867439
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发表时间：
2019-01-01
影响因子：
4.9
通讯作者：
Charbon, Edoardo
中科院分区：
文献类型：
--
作者：
Ulku, Arin Can;Bruschini, Claudio;Charbon, Edoardo
在本文中，我们报告的SwissSPAD 2，512 × 512光子计数像素的图像传感器，每个包括一个单光子雪崩二极管（SPAD），一个1-B存储器，和一个门控机制能够打开和关闭SPAD，与250和344 ps的偏斜，分别为5.75 ns的最小持续时间。该传感器的设计，以实现高达每秒97 700二进制帧的帧速率和子40 ps门移位。通过将其与脉冲激光同步并使用多个连续的重叠门，可以重建具有皮秒时间分辨率的分子的荧光响应。得益于传感器的像素数量（迄今为止最大的）和完全集成的门控操作，SwissSPAD 2能够以相对较高的帧速率使用全固态解决方案实现宽视场荧光寿命成像显微镜。这是证明了与有机染料和半导体量子点，使用衰减拟合和相量分析的初步结果。此外，具有极低暗计数率和高光子检测概率的像素能够对用多种染料染色的生物相关荧光样品进行均匀和高质量的成像。虽然未来的版本将增加微透镜并优化固件速度，但我们的研究结果为商用科学时间分辨成像仪的低成本替代品开辟了道路。
In this paper, we report on SwissSPAD2, an image sensor with 512 x 512 photon-counting pixels, each comprising a single-photon avalanche diode (SPAD), a 1-b memory, and a gating mechanism capable of turning the SPAD ON and OFF, with a skew of 250 and 344 ps, respectively, for a minimum duration of 5.75 ns. The sensor is designed to achieve a frame rate of up to 97 700 binary frames per second and sub-40 ps gate shifts. By synchronizing it with a pulsed laser and using multiple successive overlapping gates, one can reconstruct a molecule's fluorescent response with picosecond temporal resolution. Thanks to the sensor's number of pixels (the largest to date) and the fully integrated gated operation, SwissSPAD2 enables widefield fluorescence lifetime imaging microscopy with an all-solid-state solution and at relatively high frame rates. This was demonstrated with preliminary results on organic dyes and semiconductor quantum dots using both decay fitting and phasor analysis. Furthermore, pixels with an exceptionally low dark count rate and high photon detection probability enable uniform and high-quality imaging of biologically relevant fluorescent samples stained with multiple dyes. While future versions will feature the addition of microlenses and optimize firmware speed, our results open the way for low-cost alternatives to commercially available scientific time-resolved imagers.