Simultaneous fluorescence lifetime and Raman fiber-based mapping of tissues

We report the development of a novel, to the best of our knowledge, fiber-based system to realize coregistered simultaneous acquisition of fluorescence lifetime (FL) data and Raman spectra from the same area. FL measurements by means of time-correlated single photon counting are realized with periodic out-of-phase external illumination of the field of view, enabling acquisition of data under bright illumination of the specimen. Raman measurements in the near-infrared are realized asynchronously. We present a detailed characterization of this technique and validate its potential to report intrinsic contrast. Fiber-based FL and Raman maps report complementary structural, compositional, and molecular contrast in biological tissues with diverse compositional features.