Half-integral spiral phase plates for optical wavelengths

Abstract

We have fabricated high-quality, half-integral spiral phase plates for generating optical vortices at visible and near-infrared wavelengths. When inserted in the waist of a fundamental Gaussian beam, such a device gives rise to a rich vortex structure in the far field. The near-perfect cancellation of the effect induced by two nominally identical phase plates shows that we have excellent control of the manufacturing process.