Holographic patterning of block copolymers

The combination of a top down (holographic patterning (HP)) and a bottom up (Block Copolymer (BCP) self assembly) fabrication techniques resulted in a series of hierarchical nanostructures. This produced a long range uniform layered structure with a periodicity of $\sim $200 nm from HP and a finer structure on $\sim $10 nm scale due to BCP self assembly. The difference in refractive indexes of the BCP and crosslinked network results in a transmission spectrum with $\sim $100{\%} background transmission and a modest reflection notch in the visible region. Furthermore, upon heating, the BCP HP produces a red shift in the reflected wavelength of the material, which reverses upon cooling. Thus, combining HP and BCP offers a unique means to fabricate novel multifunctional optical components.