We present a spiral phase filtering system with a large tolerance for edge enhancement of both phase and amplitude objects in optical microscopy.The method is based on a Fourier 4-f spatial filtering system.A phase mismatched spiral phase plate （SPP） fabricated by electron beam lithography is employed as the radial Hilbert transform for image edge enhancement.Compared with holography,SPP is simple,economical,reliable,and easy to integrate.
An optimized iterative technique combining the merits of conventional Gerchber-Saxton （G-S） and adaptive-additive （A-A） algorithms to design multilevel computer-generated holograms for the creation of a desirable structured intensity pattern for multiple optical manipulation is theoretically adopted. Optical trap arrays are demonstrated with the help of liquid crystal spatial light modulator and a microscopic optical tweezer system. Additionally, continuous locked-in transport and deflection of microparticles with the generated optical lattice is proven experimentally. The proposed method possesses apparent high efficiency, high uniformity, and dynamic and reconfigurable advantages.
