We propose and demonstrate what is to our knowledge a novel technique of improving the spatial resolution of an optical coherence tomography (OCT) system given a non-Gaussian light source spectrum. By using dispersive materials in the reference arm of the OCT system, the resultant dispersion variation led to a full-width at half maximum (FWHM) of the interference fringe envelope smaller than the Fourier transform-limited value of a Gaussian spectral shape with the same spectral FWHM, at the expense of significant tails. The effects of the tails, which would blur the OCT images, were tremendously reduced with a retrieval algorithm. Simulation results and processed OCT scanning images have shown the capability of the proposed technique.