SBIR Phase II: Dual-Wavelength Picosecond Fiber Laser Source for Label-Free Microscopy

This Small Business Innovation Research (SBIR) Phase II project aims to develop a novel research microscope based on coherent Raman scattering (CRS). In contrast to other techniques, CRS is a label-free method that requires excitation with two synchronized laser pulse trains (ultra-short pulse duration) with precisely tunable wavelengths (<1nm). The key innovation of the Phase I proposal was the realization that the difference frequency of the two major gain media used in the telecommunication industry, Erbium and Ytterbium, corresponds to the wavelength range where most CRS imaging is performed. This provided a path to an economical laser source for CRS based on a robust all-fiber implementation of low-cost telecom components. Following successful proof-of-concept in Phase I, the Phase II proposal aims to complete the development of the laser system and integrate it into an easy-to-use and environmentally stable solution for CRS microscopy. The broader impact/commercial potential of this project is in the area of biological and material science research, and ultimately medical diagnostics. CRS allows microscopic imaging with chemical contrast based on intrinsic spectroscopic properties of the sample. It circumvents the issues associated with fluorescent labeling or dye staining, which can be especially problematic for imaging molecules that are smaller than typical labels or for use in vivo in patients. Wide ranging applications including studying lipid metabolism, trans-dermal drug delivery, biomass conversion to biofuel, and tumor margin delineation during cancer surgery, have been demonstrated. Current laser systems for CRS are expensive, require experienced personnel for operation, and are not robust. This greatly limits access to this exciting new technology and prevents use in medical diagnostics. The proposed integrated CRS microscopy solution aims to overcome these limitations.