Mid-infrared Laser-Induced Fluorescence with Nanosecond Time Resolution Using a Superconducting Nanowire Single-Photon Detector: New Technology for Molecular Science

ConspectusIn contrast to UV photomultiplier tubes that are widely used in physical chemistry, mid-infrared detectors are notorious for poor sensitivity and slow time response. This helps explain why, despite the importance of infrared spectroscopy in molecular science, mid-infrared fluorescence is not more widely used. In recent years, several new technologies have been developed that open new experimental possibilities for research in the mid-infrared. In this Account, we present one of the more promising technologies, superconducting nanowire single photon detectors (SNSPDs) by sharing our experience with its use in a typical experiment carried out by physical chemists (laser-induced fluorescence) and comparing the SNSPD to a detector commonly used by physical chemists (InSb at LN Temperature).SNSPDs are fabricated from a thin film of superconducting metal, patterned into a meandering nanowire. The nanowire is cooled below its superconducting temperature, Tc, and held in a constant current circuit below...