Measurement of the complex refractive index of tissue-mimicking phantoms and biotissue by extended differential total reflection method

Abstract

Refractive index of biotissue is a useful optical parameter in the biomedical field. An extended differential total reflection method is introduced to determine the complex refractive index. The real part is directly determined by differential of the reflectance curve, and the imaginary part is obtained from nonlinear fitting. The method is verified by a series of tissue-mimicking phantoms, porcine muscle and porcine adipose.

Wavelength dependence of the refractive index of human colorectal tissues: comparison between healthy mucosa and cancer

“…By using polarized laser light as the illuminating beam of the prism/tissue setup at different angles, the amount of reflected light is measured. By knowing the RI of the prism at the laser wavelength, the RI of the tissue can be calculated by identifying the critical angle at the prism/tissue interface [1,4,[7][8][9][10]. This method is very simple and it can be used to measure the RI of biological tissues at different wavelengths, provided that lasers at those wavelengths are available.…”

Two-dimensional scanning focused refractive-index microscopy and applications to refractive-index profiling of optical fibers

“…The critical angle is located at the maximum of the first derivative of the reflectance curve. 28 Then the n s can be obtained. The spatial resolution along the X-axis is smaller than the illuminated area on the fiber because only the data near the first derivative of reflectance curve are required to calculate θ c according to the DTRM.…”

“…We focus the incident light on the prism-fiber interface and obtain the reflected light of different points of the fiber through scanning the end face. Based on derivative total reflection method (DTRM), 28 we can obtain the quantitative RIP of the optical fiber. The SFRIM that we presented before is more suitable for one-dimensional measurement since the size of light spot will change in 2-D measurement.…”

Measurement of refractive index distribution of biotissues by scanning focused refractive index microscopy

“…The widely adopted total internal reflection (TIR) method plays an important role in RI measurements. [12][13][14][15][16] Most traditional TIR methods obtain the average RI of the illuminated area (mm 2 level) by measuring the angle-dependent reflectance curve. The low spatial resolution of TIR methods makes Pressure Pressure 1 T it difficult to observe subtle tissue information and limits its application for the measurement of spatially resolved RI imaging.…”