Refractive index measurements of tissue and blood components and OCAs in a wide spectral range

This chapter presents methods for measuring the refractive index (RI) of biological tissues and blood and their components in a wide range of wavelengths. The advantages and disadvantages of these methods are analyzed. The data for RIs of various biological tissues and blood components measured in vitro, ex vivo, and in vivo in a wide spectral range are summarized. The RI kinetics during immersion optical clearing (OC) of tissues and blood are analyzed. The chapter also describes RI measurements of optical clearing agents (OCAs) using THz pulse spectroscopy.E.N.L. was supported by RFBR grant 20-32-90058-postgraduate students; V.V.T was supported by grant of the Government of the Russian Federation 075-15-2021-615; I.Y.Y. and A.N.B. were supported by RFBR grant 18-52-16025 NTSNIL_a, and D.K.T. was supported by the RF Presidential grant for young scientists SP-3507.2018.4. L.O. was supported by the Portuguese Science Foundation, grant # FCT-UIDB/04730/2020. The work of K.I.Z. on Sect. 7.8 was supported by the Russian Science Foundation (RSF) project #17-79-20346.