The Complex Photonic Systems (COPS) chair has excellent facilities for its research. The facilities include a fully equipped chemical lab and a state-of-the-art physical lab with top-class instruments. Our technicians make sure that all the researchers can focus on science.

Below please find descriptions of several setups and pictures of these facilities. Click on a picture to see a bigger version.

Active wave front control
In our lab we have several setups where we actively control the spatial wave fronts of incident light using liquid crystal and DMD spatial light modulators. Using these advanced setups we control the propagation of light in strongly scattering samples, including photonic band gap crystals. By precisely matching the wave front to the scattering we have managed, as the first ever, to focus light behind samples that are completely opaque. In one of our setups the wave front control is combined with a high sensitivity fluorescence microscope and a nano position stage, which enable us to illuminate fluophores hidden deep inside opaque materials.

White-light spectroscopy using Fianium sources
The super continuum fiber laser is a versatile high power white light laser with output ranging from wavelengths of 450 nm to 2400 nm. It is pulsed with pulse durations less than 10 ps. We use this laser for reflectivity and transmission experiments on nanostructures (e.g. photonic band gap crystals) and for total transmission experiments to measure the scattering mean free path of strongly scattering materials over broad wavelength ranges. We also use this laser source for time-resolved emission experiments to probe the local density of states in ordered and disordered photonic materials.

Narrowband tunable Ti-Sa laser
With a Coherent Verdi-10 single-line 10-W 532-nm ND:YAG laser, we pump a Coherent MBR-110 continuous wave Ti:Sapphire laser. The MBR-110 (MW) laser is broadly tunable from 750 to 940 nm, and has a narrow linewidth of less than 100 kHz. Its frequency is stabilized to a reference cavity and modehop-free sweeps of more than 30 GHz are feasible.

Time-resolved measurements of single emitters
For time-resolved emission measurements on single emitters (e.g. quantum dots) we have a Time-Correlated-Single-Photon-Counting (TCSPC) setup. The single emitters are optically excited with a set of pulsed diode lasers, or with a mode-locked Nd:YAG laser (Time Bandwidth). Excitation is done through a microscope objective to limit the stray signal from other emitters. The emission is filtered with a set of band pass and cut-off filters. The sample is positioned with help of a CCD camera. Time resolved emission is detected by a single-photon avalanche photodiode with a time resolution of 250 ps (in the visible) or an InGaAs photomultiplier (in the near IR). The signal is then analyzed by Picoharp 200 TCSPC counting board. If needed, samples can be cooled to He-temperature with a choice of cryostats.

Images
You can find some images of our setups and facilities here.