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Optical responses of condensed matters in cryogenic environment constitute important topics in experimental and engineering studies – the signal responses become more evident and physical process purer at low temperature, and the evolution against temperature reveals important physics. Oxford Instruments is dedicated to providing fine environment vehicles with a variety from cryogen-cooling to Cryofree®, from macro optics to micro ones, as well as the additional dimension of magnetic field; this enables an application spectrum driving the materials science studies incrementally and continuously evolved.
Raman Scattering or the Raman effect is the inelastic scattering of a photon by molecules which are excited to higher vibrational or rotational energy levels. It is used to analyse a wide range of materials, including gases, liquids, and solids. Highly complex materials such as biological organisms and human tissue can also be analysed by Raman spectroscopy. Oxford Instruments' optical cryostats are used to study Raman Scattering - the type of cryostat will depend on your requirements in terms of sample environment (vacuum or exchange gas) and cooling technology (nitrogen, helium or Cryofree).
Photoluminescence (PL) is commonly used for investigating semiconductors that can be studied at room temperature. At low temperatures, spectral lines are sharper and more intense, revealing more structure. Also excitations normally masked by the high thermal phonon background at room temperature become observable at low temperatures. Oxford Instruments' optical cryostats are used to study photoluminescence - the type of cryostat will depend on your requirements in terms of sample environment (vacuum or exchange gas), cooling technology (nitrogen, helium or Cryofree) and whether you are doing macro-PL or micro-PL.
Ultraviolet–visible spectroscopy or UV/VIS refers to absorption spectroscopy or reflectance spectroscopy in the ultraviolet-visible spectral region. It is routinely used in material science and analytical chemistry, commonly carried out in gas, solutions or vacuum environment. Oxford Instruments' optical cryostats are used to study UV/VIS - the type of cryostat will depend on your requirements in terms of sample environment (vacuum or exchange gas) and cooling technology (nitrogen, helium or Cryofree).
Infrared and Terahertz spectroscopy is widely used for polymer research, inorganic chemistry, pharma or drug related research, solid state and semiconductor physics. The combination of these techniques, particularly FTIR and THz spectroscopy can provide a great insight into sample properties. Oxford Instruments' optical cryostats are used to study IR, FTIR and THz - the type of cryostat will depend on your requirements in terms of sample environment (vacuum or exchange gas) and cooling technology (nitrogen, helium or Cryofree).
Fluorescence spectroscopy is a type of electromagnetic spectroscopy that analyses fluorescence from a sample. It is used in Physics, biochemical, medical, and chemical research fields for analysing organic compounds. It has also been used in differentiating malignant skin tumors from benign. Oxford Instruments' optical cryostats are used to study Fluorescence - the type of cryostat will depend on your requirements in terms of sample environment (vacuum or exchange gas) and cooling technology (nitrogen, helium or Cryofree).
Optical microscopy involves the diffraction, reflection, or refraction of electromagnetic radiation/electron beams interacting with the specimen, and the collection of the scattered radiation or another signal in order to create an image. This process may be carried out by wide-field irradiation of the sample (e.g. standard light microscopy and transmission electron microscopy) or by scanning a fine beam over the sample (e.g. confocal laser scanning microscopy and scanning electron microscopy).
Scanning Probe Microscopy involves the interaction of a scanning probe with the surface of the object of interest. The development of microscopy revolutionised biology, gave rise to the field of histology and so remains an essential technique in the life and physical sciences.
Micro-photoluminescence or Micro-PL spectroscopy is a powerful tool for investigating the optical and electronic properties of single nanostructures. Oxford Instruments' optical cryostats are used to study Microscopy/Micro-PL - the type of cryostat will depend on your requirements in terms of sample environment (vacuum or exchange gas) and cooling technology (nitrogen, helium or Cryofree).
Photoreflectance (PR) is a very sensitive optical probe method on the electronic structure of semiconductors, especially for the band-edge structure and discrete level in the bang gap. Through a modulated pumping by laser, the reflectance signal of the sample responds sharply on critical points around the band edge and in the band gap. As a differentiated spectroscopy, it can achieve a resolution of ~meV; more importantly, either radiative or non-radiative centers in the materials can be identified with this technique, therefore more fruitful information compared with the other optical characterization techniques such as photoluminescence. With a temperature evolution, more supplementary information such as ionization energy can be extracted.
For techniques requiring optical excitation prior to or during the measurement, access for light at the chosen frequency and polarisation is necessary. Choosing the right solution to provide low vibration, large open access (ƒ/1), short working distances and a uniform optical path enables you to successfully characterise your device, down to the lowest cryogenic temperatures. Your PATHWAYS to optical access for cryogenic experiments.
Optical Access Pathways PageApp Note: New insights into the electronic structure of the c-Si interface by optical second-harmonic generation spectroscopy at temperatures ranging from 4k to 300k
Vincent Vandalon, Erwin Kessels and Ageeth Bol
Eindhoven University of Technology, Department of Applied Physics, The Netherlands