S. Kumar, Y. Li, T. Huo, H. Du, Y.P. Huang
Stevens Institute of Technology,
United States
Keywords: Raman spectroscopy, photon counting, acoustic optical tunable filter, EMCCD
Summary:
Raman spectroscopy is a highly effective technique with diverse applications, including molecular identification, drug discovery, chemical analysis, and quality control. However, it faces challenges such as low sensitivity to weak Raman scattering and interference from unwanted fluorescence. To address these issues, Surface-Enhanced Raman Spectroscopy (SERS) has been employed to enhance sensitivity. Additionally, time-resolved detection using single-photon detectors, such as single-pixel avalanche photodiodes (SAPDs), Electron Multiplying CCDs and SPAD arrays, is gaining popularity due to its advantages in sensitivity, speed, and quantum efficiency. In this benchmark study, we present—for the first time, to the best of our knowledge—a direct comparison of Raman signal detection using a traditional spectrometer, SERS, and SPAD systems with an acousto-optic tunable filter (AOTF). Our results demonstrate that single photon counting significantly improves detection sensitivity, reaching a level comparable to SERS. Moreover, time-gated and time-correlated single-photon counting with sub-nanosecond resolution effectively isolates Raman signals from fluorescence, making it highly valuable for 3D Raman imaging in chemical and biomedical applications.