Development of a pre-clinical Fourier domain low coherence interferometry system

Abstract

Fourier domain low coherence interferometry (fLCI) is an optical technique which combines the depth resolution of low coherence interferometry with the sensitivity of light scattering spectroscopy. The fLCI system uses a white light source in a modified Michelson interferometer with a spectrograph for detection of the mixed signal and reference fields. Depth-resolved structural information is recovered by performing a short-time Fourier transform on the detected spectrum, similar to spectroscopic optical coherence tomography, and analyzing the wavelength dependent variations in scattered light as a function of depth. fLCI has been demonstrated as an excellent technique for probing the nuclear morphology of a monolayer of <i>in vitro</i> cancer cells. We have built a new fLCI optical system which implements an imaging spectrograph for detection and a 4- F interferometer which uses a 4-F imaging system to re-image light scattered from the experimental sample onto the slit of the imaging spectrograph. The new system has allowed us to measure light scattered from the deepest layers of thick scattering samples, such as tissue phantoms and thick animal tissues, for the first time. We now take the first steps to quantitatively determine the diameter of scatterers within a thick experimental sample using the new fLCI system along with the fLCI data processing technique.