Nonlinear Optics

Our research on nonlinear optics is divided into the subfields below.

The nonlinear conversion of laser light in waveguides [1] can be accomplished, e.g., by four-wave mixing (FWM). By FWM, the light is altered in its spectral and/or spatial distribution via nonlinear interaction with the medium. Within this interaction, very broadband light distributions from the ultraviolet to the mid-infrared spectral region - so-called supercontinua [2] - can be generated in single-mode waveguides by the conversion of longitudinal modes. Whereas in multi-mode waveguides, also a change in the spatial light distribution can be achieved by FWM.

The transverse mode conversion is investigated in the Optical Technologies group related to its potential as a novel optical switching mechanism for future telecommunication techniques as well as for tailoring light in space and time. And supercontinuum sources are used as the basis for widely tunable light sources, e.g., for chemically-selective microscopy.

Beside our experiments we can rely on in-depth numerical simulations of the multi-mode nonlinear Schrödinger equation [3] in order to investigate new phenomena or to verify experimental measurements.

On the following pages you will find a short overview of our current research by clicking on the icon.

Fundamental Publications

[1] Agrawal G. 2012. ‘Nonlinear Fiber Optics.’ Academic Press.
[2] Dudley J M, Genty G, Coen S. 2006. ‘Supercontinuum generation in photonic crystal fiber.’ Rev. Mod. Phys. 78, Nr. 4: 1135-1184. doi: 10.1103/RevModPhys.78.1135
[3] Poletti F, Horak P. 2008. ‘Description of ultrashort pulse propagation in multimode optical fibers.’ J. Opt. Soc. Am. B 25, Nr. 10: 1645-1654. doi: 10.1364/JOSAB.25.001645

Light microscopy has become indispensable in today's society. Particularly in industry, medicine and the life sciences, microscopes are important tools, e.g., for quality control or tissue assessment. Standard light microscopy often comes down to limits in terms of spatial resolution, chemical selectivity and contrast. Accordingly, continuous research on minimal invasive contrast methods is needed to obtain more detailed information about the object under investigation.

The Optical Technologies group is improving nonlinear microscopy with new laser concepts and methods, preferably with the use of Raman scattering, which allows a chemically-selective contrast without staining the samples. Both spontaneous and coherent Raman scattering techniques are being further developed in order to enhance the spectral as well as spatial resolution of nonlinear chemically-selective microscopes.

On the following pages you will find a short overview of our current research by clicking on the icon.