Conjugate Transformation for Dispersion Compensation in Optical Coherence Tomography Imaging

In optical coherence tomography (OCT), the sample dispersion tends to increase the signal width and hence lower down the resolution, resulting in serious image quality degradation, especially for imaging over a large depth range or media with large dispersion coefficient. In this letter, instead of the conventional Fourier transformation for dispersion compensation that can compensate the image only ideally at a certain depth, a novel transformation, as called conjugate transformation, is proposed to achieve high resolution at all depth by utilizing the conjugate function of the signal itself as an optimized integral kernel. A large dispersion media of ZnSe is used as the sample to test the feasibility of this novel transformation, achieving ~1.4 times higher resolution than the conventional transformation. OCT imaging of bio-tissues with ideally compensation of sample dispersion for all the depth is experimentally demonstrated and at the same time the dispersion coefficients are also obtained.