Holographically encoded volume phase masks

We present here a method to create spectrally addressable phase masks by encoding phase profiles into volume Bragg gratings, allowing these holographic elements to be used as phase masks at any wavelength capable of satisfying the Bragg condition of the hologram. Moreover, this approach enables the capability to encode and multiplex several phase masks into a single holographic element without cross-talk while maintaining a high dif- fraction efficiency. As examples, we demonstrate fiber mode conversion with near-theoretical conversion efficiency as well as simultaneous mode conversion and beam combining at wavelengths far from the original hologram recording wavelength. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction