Tunable Raman Spectrometer (Horiba T64k/Dilor)
We operate one of the top facilities for multi-wavelength Raman spectroscopy worldwide. Raman scattering is a powerful process to study materials and physical processes because photons share their energy with material excitations. Our lab uses tunable lasers and spectrometers, covering near UV, visible and infra-red wavelength ranges. The active medium inside the lasers varies from a gas mixture of Argon in Krypton to fluid of dye molecules and crystals like Titanium Sapphire and Nd:YAG. The laser light of specific colour has extremely high peak power that we need for our studies. Various samples from macroscopic to nanoscale crystals samples containing only a few atoms are perfectly measured in these setups. When exploiting resonances we study plasmons, collective electron excitations in artificially created metallic structures. Plasmonic nanostructures illuminate their surroundings with optical near fields. Whenever a nanoscale probe is placed in the vicinity of plasmonic structure, its Raman signature will be enhanced by orders of magnitude. Our setup simultaneously resolves the vibrational and electronic degrees of freedom in a sample. This is particularly handy when they are interconnected, by for example the moiré patterns. More generally, in solid-state physics, crystal symmetries determine vibrational frequencies and electronic band structure. Both of these are studied by the resonance Raman spectroscopy, which makes it an irreplaceable tool for material science.