Friday 03 Nov 2017Strategies to enhance nonlinear optical signals at the nanoscale with Perovskite and semiconductor materials.

Rachel Grange - ETH Zrich, Switzerland

Newman Red 12:30-13:30





Nonlinear optical processes are known to be weak in bulk materials and extremely small at the nanoscale since they mainly scale with the volume. Here I will show several strategies to maximize nonlinear optical signals in nano-oxides with Perovskite crystalline structure and in III-V nanowires. First, I will demonstrate how we enhance second-harmonic generation (SHG) by using the scattering properties of individual barium titanate (BaTiO3) nanoparticles. We use the Mie resonances to achieve an SHG enhancement of four orders of magnitude within the same nanoparticle1. Our results suggest that a strong increase of the SHG signal can be obtained without using plasmonic or hybrid nanostructures2.



Besides chemically synthesized nanostructures, we developed lithography processes to obtain high aspect ratio lithium niobate (LiNbO3) nanowaveguides. We demonstrate phase-matching and use it to increase the guided SHG power by a factor of more than 40. We also increase non-phase-matched guided second-harmonic by engineering the nanowire length3–5. Those bright nanostructures can serve for developing compact efficient nonlinear optical sources or waveguides. Finally I will report on cavity effects in GaAs nanowires and on a powerful multiphoton imaging method to distinguish various crystal structures in individual nanowires6.



References



(1) Timpu, F.; Sergeyev, A.; Hendricks, N. R.; Grange, R. Second-Harmonic Enhancement with Mie Resonances in Perovskite Nanoparticles. ACS Photonics 2017, 4, 76–84.



(2) Timpu, F.; Hendricks, N. R.; Petrov, M.; Ni, S.; Renaut, C.; Wolf, H.; Isa, L.; Kivshar, Y.; Grange, R. Enhanced Second-Harmonic Generation from Sequential Capillarity-Assisted Particle Assembly of Hybrid Nanodimers. Nano Lett. 2017, Just Accep, acs.nanolett.7b01940.



(3) Sergeyev, A.; Geiss, R.; Solntsev, A. S.; Sukhorukov, A. A.; Schrempel, F.; Pertsch, T.; Grange, R. Enhancing Guided Second-Harmonic Light in Lithium Niobate Nanowires. ACS Photonics 2015, 2, 687–691.



(4) Sergeyev, A.; Reig Escale, M.; Grange, R.; Reig Escale, M.; Grange, R. Generation and Tunable Enhancement of a Sum-Frequency Signal in Lithium Niobate Nanowires. J. Phys. D. Appl. Phys. 2017, 50, 44002.



(5) Escale, M. R.; Sergeyev, A.; Geiss, R.; Grange, R. Nonlinear Mode Switching in Lithium Niobate Nanowaveguides to Control Light Directionality. Opt. Express 2017, 25, 3013.



(6) Timofeeva, M.; Bouravleuv, A.; Cirlin, G.; Shtrom, I.; Soshnikov, I.; Reig Escal, M.; Sergeyev, A.; Grange, R. Polar Second-Harmonic Imaging to Resolve Pure and Mixed Crystal Phases along GaAs Nanowires. Nano Lett. 2016, 16, 6290–6297.


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