Optically resonant organic 1D nanostructures on dielectric substrates: a dye-doped polymer patterned by focused ion-beam lithography

We explore the use of focused ion-beam (FIB) milling to produce periodic nanostructures in thin films of a dye-doped polymer. We make nano-structures with FIB on transparent glass substrates by using the conducting polymer PEDOT:PSS as the host for the dye. This facilitates an exploration of the optical properties of the nano-structured dye, in particular periodic nano-structures showing lattice resonances. We investigate how the ion-beam current can be reduced so as to only structure the organic layer, leaving the underlying substrate untouched. This approach allows for the fabrication of structures that exhibit optical diffraction without damaging the excitonic properties of the dye. We thus show that FIB allows proof-of-principle structures to be created, and different nano-structure designs to be explored. Furthermore, we demonstrate that our structures are able to exhibit a quasi-bound state in the continuum.