Valerio Flavio Gili, Luca Carletti, Fares Chouchane, Guillaume Wang, Christian Ricolleau, Davide Rocco, Aristide Lemaître, Ivan Favero, Lavinia Ghirardini, Marco Finazzi, Michele Celebrano, Costantino De Angelis, Giuseppe Leo
June 24, 2017
We report the effect of the aluminum oxide substrate on the emission of monolithic AlGaAs-on-insulator nonlinear nanoantennas. By coupling nonlinear optical measurements with electron diffraction and microscopy observations, we find that the oxidation-induced stress causes negligible crystal deformation in the AlGaAs nanostructures and only plays a minor role in the polarization state of the harmonic field. This result highlights the reliability of the wet oxidation of thick AlGaAs optical substrates and further confirms the bulk χ (2) origin of second harmonic generation at 1.55 μm in these nanoantennas, paving the way for the development of AlGaAs-on-insulator monolithic metasurfaces.