Optical Surfaces Ltd. reports on a technological development that has allowed them to produce a novel athermalized beam collimator design that delivers stable high performance across a wide temperature range.
Dr Aris Kouris - Sales Director of Optical Surfaces Ltd commented “Traditionally, beam collimators tend to defocus when exposed in environments that exhibit wide temperature variations. It is a particularly difficult task to balance both, the field centration and the defocus at the same time without having to control the environment itself or resorting to highly complex, dynamic and usually costly solutions. Our athermalized beam collimators are based upon a uniquely modified off-axis mirror design incorporating INVAR elements and a novel mechanical feature which, when combined, allows direct 100% thermal compensation. In contrast to expensive dynamic options, this is achieved passively and adaptively responding in real time while thermal variations take place. As a result, high optical performance is maintained over a wide range of temperatures (+5° C to +35° C).”
Zero expansion off-axis parabolic mirror
The high stability and performance of Optical Surfaces reflective beam collimators is further assured using a zero expansion off-axis parabolic mirror, manufactured to better than lambda/10 p-v surface accuracy. The optics within the beam collimator, are secured by the use of stress-free mounts and come pre-aligned for optimum performance. The off-axis design of Optical Surfaces beam collimators produces no central obscuration thereby ensuring highly efficient transmission is obtained. The all-reflecting design of Optical Surfaces beam collimators is achromatic and with aluminium / magnesium fluoride coatings can operate from the UV to the infrared without adjustment. The use of zero expansion glass mirror substrates contributes so that these beam collimators provide exceptional operational stability. Each system has an output port at a defined distance to the focus and a side-platform. All Optical Surfaces beam collimators provide a 20mm field ensuring full compatibility with standard black bodies.
Beam collimators manufactured by Optical Surfaces Ltd are contained in an aluminium housing with provision for fixing to an optical table. Alignment aids are provided to ensure correct beam pointing. An interferogram and OPD map is supplied with every beam collimator manufactured by Optical Surfaces.
The company's ISO 9001-2015 approved manufacturing workshops and test facilities are deep underground in a series of tunnels excavated in solid chalk. This provides an environment where temperature is naturally thermally stable and vibration is extremely low. With such stable conditions testing of high precision optical components and mirrors becomes quantifiable and reliable. In addition to these natural advantages, Optical Surfaces has invested in an extensive range of test equipment and have developed methods to ensure accurate and reliable testing.