Micro particle size measurements using modulated light scattering spectrum from SDOCT

We report an experimental study based on spectral domain optical coherence tomography (SDOCT) to get depth resolved high-frequency modulated light scattering spectrum (LSS) for polystyrene micro particles with two different sizes: 7 um and 15 um in diameter. By filtering axial line signal with a Gaussian window, and doing IFFT for the filtered signal, we get the modulated LSS for the two types of particles in a specific depth range. Then by using Hilbert transform, we reconstruct the LSS for the two samples. The reconstructed LSS were then compared to the theoretical LSS results to confirm the sizes of these two different particles. This study demonstrates the potential of using this method to determine 3D distributed particles´ size with sub micro resolution. It might also be developed to probe the size of nucleus in cells to help cellular morphology measurements.