Optimized Asymmetrical Arcsine Phase Mask for Extending the Depth of Field

Abstract

With the development of wavefront coding technique, various x-y separable phase masks have been proposed for the purpose of extending the depth of field. In this letter, a new asymmetrical arcsine phase mask combing the power and arcsine function was proposed to enrich the separable odd symmetrical family of wavefront coding phase masks. Using the simulated annealing algorithm based on Fisher information for optimization, we evaluated the performance of arcsine phase mask with four typical phase masks: the tangent, sinusoidal, improved-2 logarithmic, and cubic phase masks. The comparison results of Fisher information, defocused modulation transfer function, Hilbert space angle, and digital restoration demonstrated that the arcsine phase mask could restore clear and homogeneous images with both high fidelity and high signal to noise ratio along with a wide range of defocus, proving its superiority in extending the depth of field.