Adaptive phase plates for optical encoding systems invariant to second-order aberrations

Certain optical aberrations of imaging systems yield low resolution images. Wavefront coding has proven to minimise this problem by means of hybrid optical-digital imaging systems. The optical part usually involves a phase plate described in terms of cubic polynomials whose shape is a linear combination of (x3 + y3) and (x2y + xy2). Optimization is achieved by seeking the most appropriate linear combination with respect to the optical system's constraints. Here, we propose the shape of two pairs of phase plates such that by means of relative rotations they allow for variation of the linear combination of the cubic terms. This will enable adaptive optimization of the cubic phase to the optical system's constraints when these vary in time. Results will be illustrated with numerical simulations.

► Phase plates with surfaces in the shape of coma and trefoil. ► Adaptive wavefront coding invariant to second order aberrations. ► Relative rotation of plates results in continuously variable optical encoding.