Atomic and molecular spectroscopy, quantum optics: Generating ultracold molecules and creating a molecular Bose-Einstein condensate represents one of the exciting goals in atomic and molecular physics. In a magneto-optical trap, laser assisted formation of homonuclear and heteronuclear diatomics from cold atoms is studied. Furthermore, cold superfluid heliumdroplets of about 10 nm diameter size are produced in a supersonic beam expansion and doped with atoms and molecules whose spectra and reaction dynamics are investigated. Other projects apply high resolution laser spectroscopy to gain electronic and nuclear information on atoms, molecules, and clusters in gas discharges and beam experiments. A differential back scattering LIDAR system is available as a powerful tool of applied molecular spectroscopy. In the area of quantum optics, inner atomic interference phenomena can serve as control mechanism to modify optical properties of a medium. Studies of electromagnetically induced transparency in gas samples are pursued along these lines.

Helium atom beams can be produced with a de Broglie wavelength in the Ångstrom regime. The development of matter wave optics is subject of a new experiment. Focusing a helium beam will allow spatially resolved surface analysis of sub micrometer sized objects. A “helium microscope” will provide a non-destructive tool for the high resolution study of sensitive biological material.

Plasma and gas discharge physics: Research projects at the institute aim at developing temporally and spatially resolved optical diagnostics of plasmas by different kinds of interferometry and nonlinear optical methods beyond classical emission spectroscopy. Degenerate four-wave mixing has proven to be an excellent technique for measuring temperature and particle densities of gases in cells, jets, combustion flames and plasmas. At present, the method is modified to be applied as diagnostics of combustion flames in Otto and Diesel engines. The development of new plasma sources for special purposes represents another area of interest. As an example, experiments are underway to study concepts of suitable table top VUV and XUV laser systems.

Thermophysics: Materials properties are the subject of thermophysical measurements on superheated liquid metals by using pulse heating methods in the sub-millisecond range. Thermophysical properties such as enthalpy, electrical resistivity, thermal conductivity and thermal diffusivity are determined as a function of temperature for the solid and liquid state. Other experiments are devoted to the evaluation of the emission coefficient of liquid metals. They are performed using ellipsometric techniques.

Lighting and thermal radiation measuring techniques: Further research activities deal with lighting techniques and luminescence, in future also with thermal radiation measuring techniques. As main topic, the development of new measuring devices and techniques is considered as well as the investigation of proper materials for their use as reflection standards.

Plasma techniques and technology: Recently a new field of applied research has been established which is focused on the modification of solid body surfaces and the deposition of thin layers with special properties on such surfaces. For this purpose, plasma sources of different configurations are developed. The related investigations are mainly performed in collaboration with industrial firms.

Short Description:
Research areas at the Institute of Experimental Physics include studies of free atoms, molecules, and clusters using high resolution laser spectroscopy and ionization methods as well as nonlinear optics. Of particular interest are species at very low temperature as they can be formed by cold collisions of laser cooled atoms in magneto-optical traps or by deposition onto superfluid helium nanodroplets. At the other end of the temperature scale, hot and partially ionized gases are investigated. Here, basic plasma physics research has generated a number of applied projects in thermophysics as well as lighting, and luminescence and radiation measuring technology. A new experiment in matter wave optics has recently been added with the goal of developing a non-destructive analytical tool for the study of nanometer sized structures.
The research groups interact strongly and share experimental know-how with each other.