Since the first observation of optical trapping by Ashkin et al. [Ash86], optical tweezers have shown an intense development for manipulation and interrogation of single cells in biology and physical sciences [Pad10]. In the context of the Laser Spectroscopy and Sensing group in the Laser and Plasma Laboratory, Thorlabs and the Townes Laser Institute collaborate for the development of optical tweezers to address single particles and cells in order to obtain spectroscopic information on the structure and composition of the trapped samples.
Raman spectroscopy is the first technique to be implemented with the optical tweezers. Raman spectroscopy provides molecular information on the samples by Raman effect. This system allows then to trap, manipulate and characterize properties of micron-size particles with a single continuous laser beam. With our system, Raman spectra of single polystyrene beads and single biological cells such as yeast and red blood cells in aqueous media have been obtained.