Le Professeur Chia Chen Hsu de National Chung Cheng University, Taiwan, professeur invité à l'ENS Cachan, animera un séminaire le 14 octobre 2015, à l'invitation du LPQM.
Chia Chen Hsu de National Chung Cheng University, Taiwan
I will present the enhancement of nonlinear optical (NLO) upconversion (UC) light-mater interactions using a dielectric resonant waveguided grating (RWG) comprised of a NLO polymer thin film on top of a textured SU8 substrate with a thin intervening layer of TiO2.
The outputs of near-IR to visible NLO UC processes, such as: second-harmonic generation, third-harmonic generation [1], two-photon fluorescence [2], and upconversion fluorescence (UCF) [3], can be greatly enhanced due to guided mode resonance (GMR) of the RWG structure.
By using the RWG structure, we demonstrate that the UCF of rare earth NaYF4:Yb3+,Tm3+ nanocrystals can be enhanced 10^4 times. The strong enhancement of the NLO UC generations are achieved by first by coupling the excitation light with a guided mode of the RWG structure and then the UC output light with a second guided mode.
Our numerical simulation results obtained by rigorous coupled-wave analysis indicate that the electric field of the incident light is strongly enhanced near the interface of the TiO2 layer and the NLO polymer thin film at GMR which is the major factor for the giant enhancement of the NLO UC generations. The resonance between the visible UC generations and the waveguide structure further enhances the intensities of the UC signal.
References- J. H. Lin, C. Y. Tseng, C. T. Lee, J. F. Young, H. C. Kan, and C. C. Hsu, Optics Express 22, 2790 (2014).
- J. H. Lin, C. Y. Tseng, C. T. Lee, H. C. Kan, and C. C. Hsu, Optics Express 21, 24318, (2013).
- J. H. Lin, H. Y. Liou, C. D. Wang, C. Y. Tseng, C. T. Lee, C. C. Ting, H. C. Kan, and C. C. Hsu, ACS Photonics 2, 530, (2015).