Coherent and incoherent beam combination using thick holographic substrates

We present a mathematical model of coherent and incoherent beam combination in a thick hologram. We also derive the formulae relating the read and write angles to the read and write wavelengths for the combiner. Furthermore, we present a new technique for determining the M#, and establish that the M# required for a coherent combiner is substantially less than that needed for an incoherent one. 2003 Elsevier Science B.V. All rights reserved. PACS: 42.40; 42.40.E