An advanced technique that allows the detection of one molecule within a crystal or a cell through optical excitation. Single-molecule spectroscopy (SMS) can image at subwavelength scales, down to a dozen of nanometers. It has applications in various fields of natural science, including but not limited to biophysics, quantum physics and nanoscience. SMS helps clarify long-standing problems in chemistry and biology, such as observing and examining single molecules. It also provides critical information on the optical spectra of molecules at low temperature.
