How is the Optics Laboratory equipped?
The Optics Laboratory comprises a class 10,000 (ISO 7) cleanroom with a adjoining airlock and preparation room, a standard environment high-ceilinged laboratory with a crane for moving equipment and a dedicated laboratory for the measurement of BRDF.
The cleanroom is needed because the Laboratory often works with flight-ready hardware and also because the test environment needs to be as controlled as possible. So experiments are isolated from external vibration by placing them atop two granite-surfaced optical benches with actively controlled pneumatic legs. In turn the benches are enclosed in laminar air flow hoods to further minimise the risk of dust contamination. The cleanroom also contains a Faraday cage for testing pulsed laser sources and executing low-light-level measurements.
The BRDF laboratory takes the principle of isolation a stage further, its walls and ceiling are black-painted to minimise external stray light during reflectance testing. The tests are performed using an advanced scatterometer with angular accuracy down to less than one-tenth of a degree and an ability to detect more than 13 orders of magnitude down from the incidence beam to the relative amount of scattered light scattered away from the angle of reflection. This enormous dynamic range is one of the technique's main advantages.
Other Optical Laboratory equipment include a white-light interferometric microscope able to resolve extremely small surface height differences and visual inspection microscopes for detailed surface inspection and an optical collimator to test MTF and PSF.
It is also equipped with a small-sized vacuum test chamber to assess how wavefront errors change with the transition between air and vacuum, because ultimately all the hardware under study is destined for space.
The Laboratory is ISO 17025 certified for the use of its two large-aperture interferometers to measure surface shape as well as transmitted wavefront error of optical components and systems. It has a second ISO 17025 certificate for its annual calibration measurements of absolute irradiance from the solar simulator of ESTEC's Large Space Simulator. The same type of radiometry equipment is used for measuring energy levels of lasers and other light sources.
Last update: 30 October 2009