Many applications in the field of aerospace require the use of high-end materials. They should endure the hostile environment, need to be shock resistant, low weight and most importantly reliable with a long lifetime.
Many aircrafts and spacecrafts are equipped with numerous sensors that use optics to detect, track or identify countless things. In general, many devices are a smaller remote version of a laboratory setup on the ground. Many of these applications include remote sensing, where radiation hard diffusors out of fused silica are needed.
The sensors may need a simple transparent cover that allows UV to NIR radiation to pass through, or require some optical components (e.g. lenses or prisms). Here it is important to understand what grade of fused silica offers what transmission performance for a specific wavelength region. However, not only is the absolute value of transmission important, it may also be of interest to know what to expect in terms of bubble or inclusion size and density. This is important to judge if any scattering defects or obscurations will be in the clear aperture of the optic. More information on transmission performance.
Because the sensors are in the air (or in space), it is difficult or impractical for a technician to perform maintenance during flight. Therefore, it is paramount to use materials that can sustain the working conditions for at least the duration of the flight. For space applications, this may be several years or more than a decade. Particularly in space, the materials have to sustain a dose of ionizing radiation without significant aging or degeneration of properties. Knowing how high intensity light and radiation can damage fused silica is very valuable to select the optimum materials.
