Metal-less nonlinear photonics on a semiconductor monolithic chip is a hot and challenging research domain at the interface of electromagnetics, materials science, and technology. Frequency conversion is very efficient and phenomenologically rich in both high-Q microresonators and low-Q nanoantennas fabricated with III-V semiconductors, thanks to high c(2) and refractive index contrast, optical confinement and modal overlap. In this seminar I will report on second harmonic generation in AlGaAs suspended microdisks and AlGaAs-on-oxide nanodisks, with input wavelength around 1.55 µm. We achieved the former via the evanescent coupling between the disk and a tapered fiber in the CW regime, and the latter via the focusing of a pulsed pump beam at normal incidence. Both schemes lend themselves to interesting perspectives, among which the down-conversion with input at 775 nm and output at 1.55 µm.
Giuseppe Leo (born in 1966) received a Master in EE at “La Sapienza” University of Rome (Italy) and a PhD in Physics at the University of Orsay (France). From 1992 to 2004 he has been with the Rome-III University as assistant professor and then as associate professor. Since 2004 he has been full professor at the Paris Diderot University (France) and Head of the Nonlinear Devices group of MPQ Laboratory since 2006. His research domains include nonlinear optics and quantum optoelectronics, with a focus on AlGaAs platform. Dr. Leo has coordinated several research projects, published about 100 articles, 9 book chapters and >150 conference papers, edited 1 book and registered 4 patents. He is the director of the Denis Diderot School of Engineering.