<title>Measurement of absorption and scattering spectra of chicken breast with oblique incidence reflectometry</title>

Abstract

Oblique incidence reflectometry is a simple and accurate method for measuring the absorption and reduced scattering coefficients of turbid media. We used this technique to deduce absorption and reduced scattering spectra from wavelength resolved measurements of the relative diffuse reflectance profile of white light. In this study we measured the absorption and reduced scattering coefficients of chicken breast in the visible (400-800nm) with the oblique incidence probe oriented at 0, 30, 60, and 90 degrees relative to the muscle fibers. We found that the reconstructed optical properties varied with probe orientation. This experiment demonstrates 1) the application of oblique-incidence fiber-optic reflectometry to measurements on biological tissue and 2) the effect of structural anisotropy on optical properties.

Adaptive optics for enhanced signal in CARS microscopy

“…Optical microscopy has proved to be an immensely powerful tool for biomedical applications, allowing for subcellular-level image resolution in living systems [1,2]. A major problem in optical microscopy, however, is limited depth penetration compared to MRI and CT, because of light scattering [3], absorption and optical aberrations of the sample [4]. It is possible to improve penetration depth by utilizing longer excitation wavelengths in the near-IR region [5].…”

“…This coherent excitation leads to the generation of a strong, directional blue-shifted field at the anti-Stokes frequency ω as =2ω p -ω s . The CARS intensity is given by I as =|χ (3) | 2 •I p 2 •I s , where I p and I s are the intensities of the pump and the Stokes field respectively, and χ (3) is the third-order nonlinear susceptibility. χ (3) has vibrationally resonant and nonresonant components [12].…”

“…The CARS intensity is given by I as =|χ (3) | 2 •I p 2 •I s , where I p and I s are the intensities of the pump and the Stokes field respectively, and χ (3) is the third-order nonlinear susceptibility. χ (3) has vibrationally resonant and nonresonant components [12]. The later is independent of the Raman-shift and needs to be suppressed for high-sensitivity imaging [9].…”

Phase-function corrected diffusion model for diffuse reflectance of a pencil beam obliquely incident on a semi-infinite turbid medium

“…[1][2][3][4][5][6][7][8][9][10][11][12] Many of these techniques require or would benefit from accurate models of light transport near the point of entry. Computational models of light transport including Monte Carlo simulations [13][14][15][16] and numerical implementations of the radiative transport equation [17][18][19][20] are typically too computationally burdensome to be used for applications where rapid analysis is important.…”

“…In this paper, we extend their work to include a pencil beam obliquely incident on a semi-infinite turbid medium, and investigate the accuracy of the models by comparing them with Monte Carlo simulations. The case of oblique incidence is of noteworthy importance as a number of techniques rely on angled illumination, including oblique incidence reflectometry (OIR) and [1][2][3][4][5][6][29][30][31] angled low-coherence interferometry, [32][33][34][35][36][37][38] among others. 11 In this article, we focus on the applications of OIR, a technique that has seen great success in some clinical studies.…”