Preparation and Two-Photon Lithography of a Sulfur Containing Resin with High Refractive Index

A photonic crystal structure made with a thiirane resin (BT), which has high refractive index (1.68), has been prepared by two-photon lithography. This new brominated thiirane was prepared by the reaction of brominated epoxy (BE) and potassium thiocyanate. An iodonium salt/coumarin system was used as a photoacid generator for two-photon lithography. BT had a higher reactivity in this system than BE. A photonic crystal structure which is composed of a five layer “woodpile” structure was obtained using the BT/iodonium salt/coumarin resin.