Working with high-stability materials such as glass, Zerodur and silica – Optical Surfaces Ltd. has established itself as a premier supplier of high precision reference and transmission flats to many leading research organisations and national standards laboratories worldwide.

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 10 A rms on reference and transmission Flats up to 600mm (24 inches) in diameter.

high precision reference and transmission flats

Reference & Transmission Flats from Optical Surfaces Ltd.

All reference flats from Optical Surfaces come with full quality testing assurance. Flats up to 450 mm (18 inches) diameter are provided with a Fizeau interferometric test report, larger flats are quality assured using the Ritchey-Common test procedure.

Transmission Flats are used when measuring the surface quality or transmitted wavefront of flat surfaces or optics. Reference flats are used for measuring surface flatness of polished areas by determining the variations between work surfaces and the surface of the optical flat. Uses include 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.

Optical Surfaces Ltd has been producing optical components and systems for more than 45 years and is now accepted as one of the world’s leading manufacturers of high-precision optics for high power laser research facilities. 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 relating to high precision transmission and reference flats please contact Optical Surfaces Ltd. on +44-208-668-6126 or email