Highly Smooth Off Axis Parabolic Mirrors

Large steep angle OAP and small convex mirror produced by Optical Surfaces Ltd.

Optical Surfaces Ltd. reports that its off-axis parabolic mirrors are particularly suitable for coating using an Ion Beam Sputtering (IBS) technique that provides near 100% reflectivity thereby providing unmatched protection from thermal damage that often arises from high power continuous wave lasers.

Dr Aris Kouris, Sales Director of Optical Surfaces Ltd. explained “Surface microroughness of parabolic mirrors is an important optical quality parameter which describes features which are typically smaller than slope errors. Mirror surface microroughness, when pronounced, will cause effects that may be compared to mild scattering. For many applications such effects may not be so critical. However, for high power laser applications using off-axis parabolic mirrors as key focusing elements these effects can play an important role and therefore microroughness needs to be well controlled”. Dr Kouris added “We have undertaken a long-term study that shows that the proprietary pitch polishing techniques we use to finish off-axis parabolic mirrors produces unmatched low microroughness that do not exceed 1nm RMS. This is particularly important as only ultra-smooth off-axis mirrors can be regularly successfully coated using the ion beam sputtering (IBS) technique and attain nearly 100% reflectance and negligible absorption levels”.

Distribution of microroughness measurements

Distribution of microroughness measurements on OAPs produced using pitch-polishing technique

Off-axis parabolic mirrors (OAP’s) combine the achromatic and diffraction limited imaging properties of a parabolic mirror with the ability to deviate the light path off-axis, which is useful for most imaging systems. OAP’s offer the ability to focus collimated light without introducing spherical aberration. Additionally, unlike a centred parabolic mirror, an OAP mirror advantageously allows more interactive space around the focal point without disrupting the beam. OAP mirrors are especially suitable for broadband or multiple wavelength high power laser applications.

100% reflectivity produced by Ion Beam Sputtering technique

100% reflectivity produced by Ion Beam Sputtering technique

Using proprietary production techniques, and benefiting from a uniquely stable manufacturing environment, Optical Surfaces highly experienced and skilled engineering team are world renowned for producing fast focusing OAP mirrors with unmatched surface accuracy, surface microroughness and surface slope errors.

In recent years – Optical Surfaces have been selected by world leading high power laser research groups including AWE, ELI, LULI and CLF Rutherford as well as a growing number of academic centres of excellence to provide key OAP mirrors and other related optics for a range of demanding high-power laser applications.

For further information on high reflectivity off-axis parabolic mirrors for high-power laser experiments please contact Optical Surfaces Ltd. on +44-208-668-6126 / sales@optisurf.com. To download a copy of the study ‘How microroughness impacts optical performance’ please visit www.optisurf.com/index.php/news/technical-tips/