Solution-based single-molecule fluorescence spectroscopy is a powerful experimental tool with applications in cell biology, biochemistry, and biophysics. The basic feature of this technique is to excite and collect light from a very small volume and work in a low concentration regime resulting in rare burst-like events corresponding to the transit of a single molecule. Detecting photon bursts is a challenging task: the small number of emitted photons in each burst calls for high detector sensitivity. Bursts are very brief, requiring detectors with fast response time and capable of sustaining high count rates. Finally, many bursts need to be accumulated to achieve proper statistical accuracy, resulting in long measurement time unless parallelization strategies are implemented to speed up data acquisition. In this paper, we will show that silicon single-photon avalanche diodes (SPADs) best meet the needs of single-molecule detection. We will review the key SPAD parameters and highlight the issues to be addressed in their design, fabrication, and operation. After surveying the state-of-the-art SPAD technologies, we will describe our recent progress toward increasing the throughput of single-molecule fluorescence spectroscopy in solution using parallel arrays of SPADs. The potential of this approach is illustrated with single-molecule Förster resonance energy transfer measurements.

中文翻译：

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用于单分子荧光光谱的硅光子计数雪崩二极管


基于溶液的单分子荧光光谱是一种强大的实验工具，可应用于细胞生物学、生物化学和生物物理学。该技术的基本特征是从非常小的体积中激发和收集光，并在低浓度范围内工作，从而导致与单个分子的传输相对应的罕见的突发事件。检测光子爆发是一项具有挑战性的任务：每次爆发中发射的光子数量较少，需要较高的探测器灵敏度。突发非常短暂，需要探测器具有快速响应时间并能够维持高计数率。最后，需要累积许多突发才能达到适当的统计精度，从而导致测量时间较长，除非实施并行化策略来加速数据采集。在本文中，我们将证明硅单光子雪崩二极管（SPAD）最能满足单分子检测的需求。我们将审查关键的 SPAD 参数，并强调其设计、制造和操作中需要解决的问题。在研究了最先进的 SPAD 技术之后，我们将描述我们在使用 SPAD 平行阵列提高溶液中单分子荧光光谱通量方面的最新进展。单分子福斯特共振能量转移测量说明了这种方法的潜力。