Abstract: A fiber-optic probe for multi-modal characterization of a tissue. The fiber optic probe may comprise a first group of fibers associated with a first modality of light. The first group of fibers may comprise a first light delivery fiber and a first light collection fiber. The fiber optic probe may also comprise a second group of fibers associated with at least a second modality of light, the second group of fibers comprising a second light delivery fiber and a second light collection fiber; The fiber optic probe may also comprise a longpass filter positioned distal to the first group of fibers and a lens positioned distal to the filter. The fiber optic probe may also comprise. The fiber optic probe may include the second group of fibers bypassing the filter. The second group of fibers may bypass the filter.

Abstract: The invention provides miniature side-viewing fiber optic probes that achieve high collection efficiency by maximizing the overlap of a laser delivery fiber's illumination and a collection fiber's collection cone. The probes can be made with as few as one optical piece, in addition to the optical fibers. In one embodiment of the invention, the probes are configured for performing Raman spectroscopy. Spectroscopy systems utilizing the probes of the invention are also provided.

Abstract: The invention provides windowless fiber optic Raman probes that are directly or indirectly enclosed by one or more materials having a very low Raman signal in a desired wavenumber range that is used to evaluate a sample. In one embodiment, the very low Raman signal material is a polymer, such as a fluoropolymer, that has a very low Raman cross-section in the high wavenumber Raman region (approximately 2,600 to 3,200 cm?1) which has been shown to be useful in evaluating blood vessels for atherosclerotic lesions. Still another embodiment of the invention provides windowless side-viewing intravascular catheters for evaluating lumen walls such as blood vessel walls.