Monolithic AlGaAs second-harmonic nanoantennas
  We demonstrate monolithic aluminum gallium arsenide (AlGaAs) optical anoantennas. Using a selective oxidation technique, we fabricate such epitaxial semiconductor nanoparticles on an aluminum oxide substrate. Second harmonic generation from an AlGaAs nanocylinder of height h=400 nm and varying radius pumped with femtosecond pulses delivered at 1554-nm wavelength has been measured, revealing a peak conversion efficiency exceeding 10-5 for nanocylinders with an otpimized geometry. 
V. F. Gili, L. Carletti, A. Locatelli, D. Rocco, M. Finazzi, L.   Ghirardini, I. Favero, C. Gomez, A. Lema\^itre, M. Celebra...
physics.optics