Narrow-band frequency analysis for white-light spectroscopy diagnostics

Precancerous conditions in tissue are often characterized by a slight increase in the nuclei size of epithelium cells. There has been research in the determination of precancerous tissue using white-light spectroscopy as an optical biopsy. In this paper, we investigate white light scattering off of tissue phantoms, created with polystyrene microspheres. When analyzing scattered white light, it is well known that the size of the scatterer contributes to a specific spatial oscillation pattern as a function of the wavelength. However, when examining a mixture of two or more different sized scatterers, it is difficult to relate this oscillation pattern to the specific scatterer sizes composing the mixture. To overcome this challenge, we convert this spatial oscillation pattern into the Fourier domain, which emphasizes a signature frequency peak for each particular component of the mixture. To improve our results, we use a narrow bandpass optical filter when interrogating the sample. This reduces noise in the frequency domain and isolates a single signature frequency for each scatterer in the mixture.