Optical Characterisation

Our Optical characterisation facilities include two RAS systems and a UV-Vis Spectrophotometer.

The Applied physics research group is employing optical techniques mostly for ex-situ sample characterisation on thin film samples, using systems available in the Optical Analysis Laboratory and in CRANN Photonics.
In addition the group operates two specific systems to directly support our research themes:

Reflectance Anisotropy Spectroscopy / Magneto-Optical Kerr effect

We operate two purpose built RAS spectrometer designed in collaboration with the Surface and interface research group. The smaller, portable system with a spectral range from 0.75 - 5.5eV (1650-225 nm), is mainly used for in situ growth control of plasmonic nanoparticle arrays, or oxide (110) surfaces.

The larger system is particularly designed for infra-red measurements with a spectral range of 0.34 - 5eV (3650-250 nm) and is mostly used for ex-situ measurements. In conjunction with a 4pole magnet our RAS spectrometer can also be used as sensitive spectroscopic polar MOKE spectrometer (up to 250 mT), and with an optical cryostat all measurements can be performed at low temperatures as well (70 -300K).

UV-VIS Spectrophotometer with integrating sphere (Perkin Elmer 650S)

In conventional UV-VIS spectrophotometer it is difficult to work with rough or other highly scattering samples as scattering can not be distinguished from absorption. For haze analysis (ratio between scattered and total transmission) of transparent conducting oxides and plasmonic nanoparticle arrays we operate a system using an 150 mm integrating sphere. This allows us to differentiate between scattering and absorption as well as measure transmission and reflection of thin film samples, even on single side polished substrates.