Superpixel-based spatial amplitude and phase modulation using a digital micromirror device.
Optical Society of America
We present a superpixel method for full spatial phase and amplitude control of a light beam using a digital micromirror device (DMD) combined with a spatial filter. We combine square regions of nearby micromirrors into superpixels by low pass filtering in a Fourier plane of the DMD. At each superpixel we are able to independently modulate the phase and the amplitude of light, while retaining a high resolution and the very high speed of a DMD. The method achieves a measured fidelity F = 0.98 for a target field with fully independent phase and amplitude at a resolution of 8 × 8 pixels per diffraction limited spot. For the LG10 orbital angular momentum mode the calculated fidelity is F = 0.99993, using 768 × 768 DMD pixels. The superpixel method reduces the errors when compared to the state of the art Lee holography method for these test fields by 50% and 18%, with a comparable light efficiency of around 5%. Our control software is publicly available.
We thank Duygu Akbulut, Hasan Yılmaz, Henri Thyrrestrup, Michael J. Van De Graaff, Pepijn W.H. Pinkse, Ad Lagendijk and Willem L. Vos for discussions. This work is part of the research program of the Stichting voor Fundamenteel Onderzoek der Materie (FOM). A.P.M. acknowledges European Research Council grant no. 279248.
This is the final version of the article. Available via open access from Optical Society of America via the DOI in this record.
Vol. 22, pp. 17999 - 18009
Place of publication