Abstract
SIGNIFICANCE: Superconducting nanowire single-photon detectors (SNSPDs; also known as SSPDs) show enormous promise for low-light biomedical imaging by offering exceptional sensitivity, picosecond timing resolution, and broad spectral coverage. AIM: This perspective evaluates the role of SNSPDs by comparing their performance with other photon-counting detectors for emerging biomedical imaging applications. APPROACH: We describe the need for ultrasensitive detectors for biophotonics, summarize SNSPD operating principles, and compare their performance with established photon-counting devices. We highlight applications where SNSPDs make previously unattainable imaging capabilities possible and discuss system-level challenges and technological developments that are critical to future applications, including clinical translation. RESULTS: SNSPDs offer advantages in signal-to-noise ratio, temporal precision, and detection bandwidth, enabling deep tissue imaging, high-precision fluorescence lifetime measurements, and quantum-enhanced imaging modalities. Advances in scalable arrays, cryogenic miniaturization, and improved signal collection are reducing barriers to widespread adoption. CONCLUSIONS: SNSPDs are poised to transform photon-limited biomedical imaging. As device performance and system integration continue to advance, their adoption in imaging platforms is expected to accelerate. Combining SNSPDs with advancements in the excitation pathway, such as structured-light excitation with Bessel beams, aberration correction, and wavefront shaping, shows promise for delivering unprecedented imaging capabilities and broadening both the preclinical and clinical utility of these detectors.