Fiber bundles with integrated bandpass and notch filters for in-vivo Raman spectroscopy

Raman spectroscopy is used in many areas including pharmaceuticals, geology, chemical engineering, semiconductors, and the life sciences. More recently, Raman fiber sensors have been developed for minimally invasive applications in clinical histopathology. This paper describes the modeling, fabrication, and testing of filters directly deposited onto the excitation and collection fiber tips of a Raman probe. The narrow spectral width of laser rejection filters on the collection fibers should allow for the detection of low wavenumber Raman scattering within the “fingerprint” region. Deep blocking of the laser radiation is enabled by coating both ends of the collection fibers.