Unbiased (reference-free) phase field imaging for general optical fields including phase discontinuities

TL;DR

This paper introduces a novel, exact, and non-iterative phase imaging method for optical fields that does not require a reference beam, capable of handling complex phase discontinuities and suitable for real-time video applications.

Contribution

The authors develop a reference-free, linearized measurement technique for complex optical fields that is stable, exact, and applicable to highly fluctuating and discontinuous phases.

Findings

Method is exact and non-iterative, stable against noise.

Capable of imaging fields with phase jumps and zero amplitude areas.

Suitable for real-time, video-rate applications.

Abstract

A new numerically and experimentally tested measurement method for the local electrical light field including its phase is presented. The method is based on Self Referencing Interferograms (SRI) such as shearing interferograms. The complex electric field is the solution vector of a linear equation with the pixel resolved interference term E_2* E_1 as a parameter. Linearization of the non linear equations is achieved by using preknowledge in the intensity as obtained by a conventional image detetctor. The resulting linear equations are not based on any approximation, iterative perturbation expansion etc. but are exact. The method is non iterative and stable against noise for arbitrarily chosen test fields. Allowed fields can exhibit highly fluctuating amplitudes/phases on the pixel scale, areas of vanishing amplitude and Pi phase jumps. The spatial resolution is of pixel size. No reference beam and no diaphragms are used. The new method can be implemented as a fast, one shot per frame video system. An outlook on the space resolved measurement of non classical two photon states (including vacuum squeezed coherent states) is given.