
A – Modeling nonlinear optics down to atomic scales
The individual research projects of NOA are organized into Project Areas. In this scheme, Project Area A aims to understand and describe nonlinear optics and dynamics of light interacting with matter on subwavelength or even atomic scales. Existing schemes will be adapted and novel theoretical and numerical methods will be developed to model the light-driven response in atomically thin or confined structures and their back action on the incident field. Very often, such treatment has to reach beyond a perturbative approach. The particular challenge inherent in all theory projects lies response in atomically thin or confined structures and their back action on the incident field. on the size of the spatial scales. To be precise, atomistic features and, on an atomic scale, more extended structures must be described on the same footing. Each theory project will actively support at least two experimental projects stemming usually from both Project Areas B and C.
B – Nonlinear optics of atomically thin 2D systems
Research in Project Area B is focused on the investigation of nonlinear optics in atomically thin two-dimensional structures. Thereby, Project Area B covers the full structural diversity of two-dimensional materials ranging from novel crystalline structures, such as MoS2, to amorphous films, e.g. as provided by atomic layer deposition.
In addition, two-dimensional structures will be functionalized, e.g., by applying resonant structures, by inserting ultrathin gaps between metallic walls, or by stacking bi- or multilayers, and will be subjects of investigation. Project Area B projects will examine optically induced carrier and excitation dynamics through and along these very different two-dimensional structures and will identify the impact on the nonlinear optical properties of this novel material system. Central questions to be addressed deal with identifying the structural measures needed to increase or modify and tailor quadratic, possibly even higher-order nonlinearities of these (functionalized) two-dimensional structures.
C – Plasmon-enhanced nonlinear optics in low-dimensional hybrids
The nonlinear optical investigations performed in Project Area C focus on effective zero- and one-dimensional plasmonic hybrid systems. Metallic tips and tailor-made hybrid nanostructures are used to control light at the subwavelength scale, enabling investigations down to the single-molecule limit, e.g., with nonlinear optics tools such as Coherent Anti-Stokes Raman Spectroscopy (CARS).
Novel nonlinear spectroscopic techniques will be developed aiming at measuring ultrafast vibrational and electronic dynamics, e.g., by applying X-ray Mie scattering to monitor excitation transport or other molecular rearrangements with atomic spatial sensitivity, or by employing high order harmonic spectroscopy to image the field-driven dynamic electronic structure of hybrid nanoparticles. Advanced characterization techniques such as pump-probe photoemission electron microscopy (PEEM) will provide access to nonlinear optical dynamics in semiconductor or plasmonic nanostructures with resolution down to the atomic scale.
Z – Management of the CRC
Both NOA theoretical and experimental projects are mutually interconnected and deal with complementary aspects of nonlinear optics including the exploration of new nonlinear processes and materials.
The work will include the development of novel probes operating on scales much shorter than the optical wavelength. In order to access well-defined low-dimensional systems with atomic dimensions, state of the art nanostructuring technologies will be applied. In Jena, NOA can make use of a one-of-a-kind assembly of facilities, equipment and expertise for nanostructuring and imaging including electron beam lithography for large scale exposure, a helium ion microscope for defining and imaging structures down to the atomic level, and chemical expertise to synthetize well-defined nanoparticles and -wires and two-dimensional structures. To ensure the efficiency and functionality of NOA processes, Project Area Z has been accordingly designed. It comprises an integrated research training group as a research training module, a management and coordination tool, and a service project dealing with nanostructure technology.