ANVILS GENERAL INFO
The excellent optical properties of diamonds have been known for a long time. However, optical applications require extended discs, not provided by natural diamonds. With the development of C.V.D., this has changed completely. Especially in the infrared, diamond exhibits numerous advantages.
Diamond is transparant from the UV (230 nm) to the far infrared. Only minor absorption bands resulting from two phonon absorption exist between 2.5 and 6 microns. Hence diamond is an ideal material for multispectral optical applications.
Diamond has no thermal generation of charge carriers at elevated temperatures, hence no "thermal run away" as in the case of Germanium under laser irradiation. Furthermore, diamond does not become nonlinear at high radiation intensities. Because of the high thermal conductivity of diamond, the energy is quickly dissipated to the edges of a diamond window. There it can be removed by appropriate heat sinks and cooling techniques. Diamond is extremely hard, wear resistant and chemically inert. It is an ideal material for hostile, highly erosive atmospheres.
Most of our optical diamond windows are used with FT-IR (Fourier Transform Infra Red). R&D Departments, analytical and quality control laboratories all over the world characterize plastics (polymers), organic chemicals, pharmaceuticals, foods, biologicals, oils & lubricants and inorganic materials (ceramics, minerals, glasses, metals) with this technology. Different set-ups are being used to make the right analysis. Because of the different properties that we mentioned above, our diamond windows allow direct observation of the behaviour of materials in your FT-IR set-up.
Diamond is the ideal sampling sensor for Attenuated Total Reflectance (ATR) accessories for commercial FT-IR spectrometres. Diamond is a hard, scratch-resistant material with a refractive index of 2.35. It is suitable for applications involving aqueous solutions from pH1 to 14, provided it is mounted in a support material which is equally acid/alkali resistant. Through the use of the rugged and inert material as diamond, sample hardness, pH range, size and volume do no longer influence the sample preparation. In this fashion, all samples can be analysed quickly and reproducibly.
We manufacture 'type IIA' diamond sensors adapted to your ATR accessories. The wavelength of these diamonds range from 4000 to 400 cm-1, with an absorption band in the 2500 - 2000 cm-1 region. We manufacture tailor-made diamond windows for your FT-IR instruments. Depending on the application, we will manufacture natural or synthetic diamond windows. This choice involves an analysis of the wavelengths you want to use. Another determining factor is the size of the diamond window. The combination of the right diamond material with the right surface polish will make your application a success.
To assure the right surface finish of C.V.D. diamond, we grind and polish the coarse grained films to the desired thickness, after deposition. For this purpose a high speed lapping machine capable of treating three samples simultaneously has been developed. Diamond wafers of upto 100 mm in diameter can be polished. The surface finish depends strongly on the process conditions. Rms roughness values as low as 20 Angstršms can be achieved under optimized conditions.