Design of pupil filter for extended depth of focus and lateral superresolution in Optical Coherence Tomography

摘要

A seven-zone pupil filter which can extend the depth of focus (DOF) and provide lateral super resolution in Optical Coherence Tomography is designed. Both amplitude and phase of the transmitted light beam are modified in each zone. The scalar diffraction theory is used to optimize the zone parameters. A broadband source spectrum and a Gaussian beam profile has been taken into account for the design of this filter. Several filters have been reported to extend the depth of focus (DOF) and improve the resolution but they take the assumption that a monochromatic and uniform light beam is used. With the proposed filter the DOF in OCT can be extended by 14 times while the lateral resolution can be improved by a factor of 1.47 and maintained constant within this DOF.