Fabrication of nonlinear optical devices in ionically self-assembled monolayers

Abstract

Abstract. The development of both “soft” and “hard” fabrication tech-niques for the patterning of nonlinear photonic devices in ionically self-assembled monolayer ISAM films is reported.Acombination of electronbeam lithography and reactive ion etching was used to pattern two-dimensional holes with a lattice of 710 nm and diameters ranging from550 to 650 nm. A soft alternative to this fabrication was also demon-strated. Nanoimprint lithography was successfully employed to patternsimilar photonic structures with average hole diameters of 490 nm and alattice spacing of 750 nm, as well as Bragg gratings with a period of620 nm. Potential impact of this fabrication process on the chemicalcomposition and nonlinear properties of the ISAM films was assessedusing Fourier transform infrared spectroscopy, x-ray photoelectron spec-troscopy, and second harmonic generation. The spectroscopy tech-niques confirmed that the chemical composition and bonding of theISAM films was not adversely affected by the thermal cycles required fornanoimprinting. Second harmonic generation analysis also confirmedthat the nanoimprinting process did not affect the nonlinear properties ofthe material, PCBS/PAH ISAM films, further indicating the suitability ofsuch materials for the nanoimprinting of nonlinear optical photonicstructures.