title: Strong guided mode resonant local field enhanced visible harmonic generation in an azo-polymer resonant waveguide grating.
abstract: Guided mode resonance (GMR) enhanced second- and third-harmonic generation (SHG and THG) is demonstrated in an azo-polymer resonant waveguide grating (RWG), comprised of a poled azo-polymer layer on top of a textured SU8 substrate with a thin intervening layer of TiO2. Strong SHG and THG outputs are observed by matching either in-coming fundamental- or out-going harmonic-wavelength to the GMR wavelengths of the azo-polymer RWG. Without the azo-polymer coating, pure TiO2 RWGs, do not generate any detectable SHG using a fundamental beam peak intensity of 2 MW/cm(2). Without the textured TiO2 layer, a planar poled azo-polymer layer results in 3650 times less SHG than the full nonlinear RWG structure under identical excitation conditions. Rigorous coupled-wave analysis calculations confirm that this enhancement of the nonlinear conversion is due to strong local electric fields that are generated at the interfaces of the TiO2 and azo-polymer layers when the RWG is excited at resonant wavelengths associated with both SHG and THG conversion processes.
authors.forename: Jian Hung
authors.initials: JH
authors.lastname: Lin
authors.forename: Chun-Yen
authors.initials: CY
authors.lastname: Tseng
authors.forename: Ching-Ting
authors.initials: CT
authors.lastname: Lee
authors.forename: Jeff F
authors.initials: JF
authors.lastname: Young
authors.forename: Hung-Chih
authors.initials: HC
authors.lastname: Kan
authors.forename: Chia Chen
authors.initials: CC
authors.lastname: Hsu