Beyond the “rainbow” – Chromatic correction of DOE based 3D multiplane imaging system

A diffractive optical element (DOE), in the form of an off-axis Fresnel zone plate, can be used for imaging multiple object planes simultaneously on a single image plane. This DOE based technique is compatible with all wide-field imaging modes, i.e. fluorescence, phase contrast, bright field, etc. However, due to the chromatic smearing of DOE, a narrow band filter is always applied in the imaging system, thus limiting the incident spectral bandwidth, restricting photon flux and hindering application to multiple fluorophore life science imaging. Here I will demonstrate the dispersion property of DOE, as well as the use of grism (a grating combined with prism) pair for chromatic correction by simply changing the grism separation in an unfolded, axial, optical system. The optimized phase-contour design and error budget of DOE will also be discussed. Analytic approaches combined with optical and biological experiments, our simple, linear DOE-grism based system can deliver chromatically-corrected, high-efficiency, multi-colour, multi-plane 3D imaging.