Electrically switchable gratings formed using ultrafast holographic two-photon-induced photopolymerization

Electrically Switchable Gratings Formed Using Ultrafast Holographic Two-Pho ton-Induced Photopolymerization Periodic gratings were formed using ultrafast holography to initiate two-ph oton-induced photopolymerization of a reactive monomer mixed with liquid cr ystal. The resulting structure shown in the cross-sectional SEM micrograph (scale bar = 3 mum) consists of periodic lamellae of polymer-dispersed liqu id crystals and dense polymer. This periodic structure generates a refracti ve index modulation that gave rise to diffraction of light. The far-field d iffraction intensity pattern can be modulated by applying an electric field across the holographic grating.