Backscattering spectroscopic contrast with angle-resolved optical coherence tomography.

Backscattering spectroscopic contrast using angle-resolved optical coherence tomography is demonstrated as a powerful method for determining scatterer diameter with subwavelength resolution. By applying spectroscopic digital processing algorithms to interferograms acquired in the frequency domain with a wavelength-swept laser centered at 1295 nm, it was shown that differences in wavelength-dependent backscattering from 0.3 and 1 microm diameter microspheres can be clearly resolved. The observed backscattering spectra were found to be consistent with Mie theory. High levels of speckle noise reduction achieved by angular compounding increased the spatial resolution at which backscattering spectra could be accurately differentiated.