Orthonormalization of phase-only basis functions

Abstract

Generation of orthonormal optical fields using phase-only spatial light modulators (SLM) or amplitude-only digital micromirror devices (DMD) is an active and diverse research field, with a wide variety of applications. However, these approaches typically come with limited accuracy, and a significant loss in resolution and intensity. We present a different approach: we construct orthonormal fields that can be generated exactly on phase-only hardware without loss of resolution or intensity. Our method can use any set of fields as a starting point and orthonormalize them. Our approach allows control over application-specific requirements such as smoothness, symmetry and overall shape. In many use cases, sets of orthonormal fields can be used as a 'drop-in replacement' for other sets of fields. We demonstrate the practical benefit of our approach in a wavefront shaping experiment, achieving a factor 1.5 increase in performance over a non-orthonormal phase-only basis.