Wavefront conversion by volume holograms between cylindrical and plane waves

The efficiency of lossless volume holograms in converting plane and cylindrical waves into each other is analysed and the results are plotted as a function of the normalised thickness of the hologram. A coupler consisting of two separate holograms, and capable of converting a divergent cylindrical wave into a convergent cylindrical wave, is also investigated, and it is shown that under favourable conditions an overall efficiency of 98.3% may be obtained.