STAGE offre de stage :Nonlinear and quantum nanophotonics in semiconductor nanowires

Until recently, a full development of an AlGaAs photonic platform has been hindered by the difficulty of fabricating monolithic shallow waveguides and cavities with high refractive-index contrast as in the silicon-on-insulator (SOI) system. This is due on one hand to the technological burden of hybridizing Aluminium Gallium Arsenide (AlGaAs) on SOI via wafer bonding, and on the other hand to the shortcomings of the selective oxidation of AlGaAs epitaxial layers. While the use of Aluminium Oxide (AlOx) layers thinner than 100 nm is used in VCSEL technology and enabled our group to demonstrate an optical parametric oscillator in an AlGaAs waveguide [1], the fabrication of high-quality µm-thick AlOx optical substrates is critical because the selective oxidation of AlGaAs optical substrates induces a strong contraction of the oxide and important optical losses in integrated photonic devices due to defects at the interface between AlOx and the adjacent crystal.

This internship proposal stems directly from the technological breakthrough performed by our team in 2016 [2], resulting in the fabrication of AlGaAs layers on top of a good-quality optical substrate of AlOx. With this know-how, we have demonstrated the first AlGaAs monolithic optical nanoantenna, and the smallest controllable second harmonic generation (SHG) source to date [3].