Fourier transform-based continuous phase-plate design technique : a high-pass phase-plate design as an application for OMEGA and the National Ignition Facility

A technique capable of calculating near-field, continuous phase diffractive optics (or phase plates) without phase dislocations and with optional far-field, speckle-spectrum control is introduced. The design technique improves upon a standard phase-retrieval method by adding convergence enhancements, phase continuity control, and far-field, speckle-spectrum control. The convergence enhancements improve the algorithm's efficiency. Phase continuity control eliminates phase dislocations and mitigates damaging retroreflections and transmissions. Specifying an optional constraint controls the far-field speckle spectrum. Application of these phase plates on the OMEGA and National Ignition Facility laser systems would produce well-controlled far-field spot shapes. High-pass phase-plate designs are compared with designs where the far-field spectrum is not controlled.