Mesogenic versus non-mesogenic azo dye confined in a soft-matter template for realization of optically switchable diffraction gratings

We report on fabrication and characterization of two different kinds of optically controlled diffraction gratings realized in soft composite materials. The periodic microstructures have been obtained by combining a photolithographic technique and a chemical etching process. The samples have been infiltrated with two classes of photosensitive materials, and then characterized. The first material is a common azo-dye dissolved in a liquid crystal (LC), while the second one is an azobenzene LC (azo-LC). The response and relaxation times, lifetimes and spectral absorption range of the LC mixtures confined in the microstructures were measured. Detailed comparison of investigated characteristics reveals a better overall performance of the azo-LC based sample. © 2011 The Royal Society of Chemistry.