Gigahertz-Optik's Integrating Sphere Recoating Services
Did you know that Gigahertz-Optik not only manufactures integrating spheres but also offers on-site recoating services for large diameter spheres using its own formulated Barium Sulfate
In order to maintain its high reflectance and integrity integrating spheres require periodic refurbishment especially a recoating of its internal surface. Over time and usage optical quality diminishes due to environmental contamination, high temperature operation of high output light sources under test and degradation due to ultraviolet emission and humidity.
Gigahertz-Optik offers integrating sphere recoating services employing its own ODP97 barium sulfate (BsSO4) formulation. For large diameter spheres this service is done on site after fully enclosing and isolating the service area.
For example, we recently refurbished and recoated the METAS sphere in Bern, Switzerland. The Swiss Federal Institute of Metrology METAS is the federal government's center of competence for all matters relating to measurement, measuring equipment and measurement procedures. METAS is the Swiss equivalent of the Physikalisch-Technische Bundesanstalt (PTB) in the Federal Republic of Germany or the National Institute of Standards and Technology (NIST) in the USA, to name but two others. Note that recently Gigahertz-Optik also recoated NIST’s large diameter sphere in Gaithersburg, MD.
As far as we know, METAS currently houses the largest integrating sphere in Europe with a diameter of nearly four meters. This sphere was previously inactive for several years due to the discoloring of its coating over its decades of use.
For recoating purposes, Gigahertz-Optik pre-produced more than 70 litres of a customized solution of barium sulfate coating with the desired 90 percent reflectance in a complex and absolutely reproducible manufacturing process. This amount of barium sulfate was required for a sphere of this size and the many coating layers required for a very high homogeneity and to reduce 'pooling'. Luckily Gigahertz-Optik’s own BaSO4 formulation is water based instead of alcohol based leaving the spray operator intoxication free.
Application of the coating was carried out in a vacuum tent specially erected for the coating job in order to ensure cleanliness in the calibration laboratory there and not to endanger other sensitive optical equipment such as a mirror goniometer. Here, the preparation by METAS was outstanding! Due to the sphere size, the unique coating technique was a special challenge. The coating and the associated work on the integrating sphere took a week by sphere specialists from Gigahertz Optik GmbH and METAS.
Please contact us if you have an integrating sphere requiring refurbishment and recoating or if you wish to purchase our own ready-to-apply barium sulfate. Of course new standard or custom designed integrating sphere inquiries are also welcome.