Large transmission flat in protective hardwood box.

Working with high-stability materials such as glass, Zerodur and silica, Optical Surfaces Ltd is today recognised as a premier supplier of high precision reference flats by many leading research establishments and national standards laboratories.

Reference flats are a proven method of measuring the surface accuracy or the transmitted wavefront of flat surfaces or optics. Benefiting from a unique thermally stable manufacturing environment – Optical Surfaces Ltd. is able to routinely achieve a surface accuracy of lambda/20 p.v. and surface roughness of less than 1nm on reference flats up to 600mm in diameter. Optical Surfaces reference flats are used in high precision applications in astronomy, laser beam steering, inspecting gauge blocks for wear and accuracy and interferometric flatness testing of prisms, filters and optical windows.

All reference flats from Optical Surfaces Ltd. come with full quality testing assurance. Optics up to 450 mm diameter are provided with a Fizeau interferometric test report, larger flats and spheres are quality assured using the Ritchey-Common test procedure.

Optical Surfaces Ltd has produced reference flats for more than 45 years and is now accepted as one of Europe’s leading manufacturers of high-precision optics. The company’s ISO 9001-2008 approved manufacturing workshops and test facilities are deep underground in a series of tunnels excavated in solid chalk where temperature remains constant and vibration is practically non-existent. With such stable conditions testing, particularly with long path lengths, becomes quantifiable and reliable. Working with these natural advantages is a highly skilled team of craftsmen with a commitment to excellence in both product quality and customer service.

For further information please contact Optical Surfaces Ltd. on telephone +44-208-668-6126 or email