  In this work, we report the application of Raman microspectroscopy for
analysis of the refractive index of a range of tissue phantoms. Using both a
custom-developed setup with visible laser source and a commercial
micro-spectrometer with near infrared laser, we measured the Raman spectra of
gelatin hydrogels at various concentrations. By building a calibration curve
from measured refractometry data and Raman scattering intensity for different
vibrational modes of the hydrogel, we determined the refractive indices of the
gels from their Raman spectra, with approximately the same accuracy as that of
refractometry measurements with an Abbe refractometer. This work highlights the
importance of a correlative approach through Brillouin-Raman microspectroscopy
for the mechano-chemical analysis of biologically relevant samples.
