Photonic crystal slab biosensors fabricated with helium ion lithography (HIL)

A photonic crystal slab is a periodic arranged dielectric nanostructure which can be used in many applications, such as a label-free optical biosensor. This work demonstrates a novel nanofabrication process using helium ion lithography (HIL) for the rapid prototyping of master molds, which can be repeatedly used for fabricating photonic crystal slabs by nanoimprint lithography. To prove the concept, photonic crystal slabs with nano-grating and nano-hole patterns have been fabricated and the results show that the photonic crystal slabs fabricated by the HIL in conjunction with the nanoimprint lithography demonstrate photonic bandgaps. The functional tests demonstrate that the fabricated nano structures can be utilized as refractometric sensors to detect changes of the refractive index caused by adsorption of biochemicals. This fabrication approach offers a new route for mass-production of high-quality photonic crystal biosensors with a variety of nano-patterns. (C) 2019 Elsevier B.V. All rights reserved.