Optimizing the generalized phase contrast method for a planar optical device

We analyse and optimize the output of a planar optical device implementing the generalized phase contrast method. Surface-integrated diffractive micro-optical components build up a spatial filtering-based common-path interferometer consisting of a 4 f lens configuration with a phase contrast filter etched as a 5 μm diameter steep-edged cylindrical hole at the Fourier plane. This filter is designed for operation at λ = 632.8 nm and carries out a phase shift of π for the on-axis region of the focused light. The performance of the device is analysed in terms of throughput and visibility of input phase patterns. A practical design for improved performance is also evaluated for application in visualization of two-dimensional phase patterns as applied in electro-optical data communications, particularly in security and product authenticity verification applications.