The research area "Materials" contains all projects, where the control or the theoretical description of material properties is central:
In project B01 ZnO is in the main focus. High-quality low-dimensional quantum systems based on ZnO are fabricated using MBE. The confinement leads to an enhancement of nonlinear processes such as second and third harmonic generation as well as two- and three-photon absorption due to exciton effects. Novel spectroscopic methods are developed in order to investigate the nonlinear effects and the influence of external fields and symmetry-breaking.
Project B02 continues with the fabrication of cubic GaN/Al(Ga)N heterostructures and the investigation of their ultrafast and/or nonlinear optical properties. The aim is to enlarge and utilize the resonant nonlinearity associated with near-infrared intersubband transitions in quantum wells. Also nonlinear metasurfaces formed by depositing antenna structures resonant to the intersubband transitions will be investigated. Here massive-ly enhanced optical nonlinearities are expected, which enable nonlinear optical frequency mixing with relaxed phase-matching conditions.
The central ab initio theory project B04 is of key importance for the CRC. It is dedicated to the prediction and description of linear and nonlinear optical properties of both semiconductor and ferroelectric materials and to method development.
The new project B05 aims at the fabrication of periodically poled waveguide structures with ultrashort periods in lithium niobate and KTP for counter-propagating parametric down-conversion. It is focused on the development of the technological processes required to achieve ultra-short domain periods in a combined technological and analytical approach in close cooperation with theoretical materials physics.