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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.
In addition to the proper optical access, appropriate windows must be fitted to permit radiation to pass through the sample space. The type of window material and surface coating selected will be determined by the wavelength and intensity of the radiation, the environmental temperature and whether or not the light is polarised.
For UV/Visible, Raman, FTIR, Fluorescence, Photoluminescence and THz applications, optical access is designed such that:
i) The system offers optimum transmission intensity
ii) There is no need to realign the optics after each sample change
iii) A wide range of interchangeable windows are available depending on the experiments
Whatever the requirements of your experiment may be, we have the solutions that will allow superior optical access for quick and efficient sample characterisation.
Our compact optical cryostats for spectroscopy offer 5 optical windows (4 radial and 1 axial), providing f/1 access in all orientations. All windows are easily exchanged in situ, keeping pace with your changing experimental needs.
The Cryofree compact cryostats come with f/1 and large clear optical access as standard. It offers a clear view of 28 mm diameter allowing a large illumination area for measurements involving the detection of low intensity light.
A range of window materials are available to suit different wavelengths; wedged windows and anti-reflection coatings are also available.
Download our Windows brochure Contact us for more informationSome specialist applications require optical and beam access into the cryogenic sample environment coupled with high applied magnetic fields. For these applications large open angle access is desirable in both the horizontal and vertical plane of the measurement. In some cases, having anti-reflective coating around the beam access aides the quality of beam cleanliness. In such large open angle access magnet systems, former design is a key consideration with significant forces generated across the coils during operation. Symmetric and asymmetric coils allow fields to be generated with offset field centre lines for polarisation measurements. Careful selection of window materials to suit the wavelength and type of beam ensures minimal transmission losses. Finally, open angle, windowed and split ring former assemblies ensure optimal access to the sample region is balanced against former and coil size and weight.
For diffraction, looking at the spatial structure of materials, X-rays and neutrons are scattered elastically so as not to exchange energy with the sample this includes small angle scattering for the study of surfaces and interfaces.
For spectroscopy, looking at the electronic and dynamic structure pf materials, X-rays, light and neutrons are scattered in-elastically exchanging energy with the sample measuring atom and lattice dynamics, vibrational and rotational states as well as chemical species, both short and long lived.
For muon spin research, similar in requirements to neutron scattering measurements, magnetometry on a microscopic scale is possible with local magnetic structure and hyperfine coupling able to be measured. These phenomena persist as dynamic phenomena and can be measured as they vary with time.
Using a polarised beam, comparison of left and right polarisations can give insight into spin species and magnetic behaviour.
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