Knight Optical (UK) Ltd Borosilicate Window Optically Polished Grade 40mmdia x 3mthk Uncoated WHP4000

We offer two grades of stock borosilicate or equivalent windows. Our standard windows are cut from float sheet material and our polished grade is then further polished to better flatness and surface quality. These borosilicate or equivalent windows listed here are made from low expansion borosilicate or equivalent glass. Borosilicate has excellent transmission over the visible and NIR wavelengths working from 310nm to 2700nm. The surface quality is not as high as the BK7 versions. Low-expansion windows are very useful in applications where they are exposed to the elements as borosilicate has excellent chemical and thermal-shock resistance and has a maximum working temperature of 500°C. Examples include use in high powered light source applications and they are an excellent choice for cold and hot mirror substrates. Borosilicate or equivalent windows can also be a good substrate for optical flats as it has low expansion properties and therefore maintains its flatness in different environmental conditions. Our stock windows are available to buy directly from this site, and we also offer an extensive custom window capability for unique shapes and sizes. For more information on our custom windows please contact our technical sales team.