Shifted-excitation Raman difference spectroscopy for in vitro and in vivo biological samples analysis.

The contamination of the Raman scattering signal with luminescence is a well-known problem when dealing with biological media excited by visible light. The viability of the shifted-excitation Raman difference spectroscopy (SERDS) technique for luminescence suppression on Raman spectra of biological samples was studied in this work. A tunable Lithrow-configuration diode laser (λ = 785 and 830 nm) coupled (directly or by optical fiber) to a dispersive Raman spectrometer was employed to study two sets of human tissues (tooth and skin) in order to determine the set of experimental parameters suitable for luminescence rejection.