FREQUENTLY ASKED QUESTIONS (FAQ’s)
Here is a sample of frequently asked questions by customers over the years. If you have any more questions or believe that we should add some more in this section please feel free to contact us.
Q. What are the size limits of your optical components?
A. Usually around 650mm, the limit is quite often because of testing constants. OS has handed up to 1m in the past and is happy to discuss your requirements.
Q. What is the smallest F-number that you can produce?
A. Around about F/0.5 – again it is the testing that is the limitation.
Q. With OAP’s what is the largest off-axis angle you can manufacture?
A. We have made mirrors with an angle of 45 degrees but it all depends on a number of other variables such as size and focal length. Again, we are happy to discuss your specific requirements.
Q. What is your typical surface microroughness figure on your optics?
A. A figure of 1.2 nm RMS with standard polishing methods would be typical. Figures of 0.4nm RMS have also been achieved when the surface roughness is a customer requirement.
Q. Can you test and calibrate old optics that is currently in use?
A. Yes it is a service that we regularly perform.
Q. What is the highest surface accuracy that you can produce?
A. Usually around λ/20 P-V at 633nm, depending on size and configuration. Accuracies better than this have regularly been produced; the test usually is the limitation. However, etalon plates matched to λ/300 P-V at 633nm are a regular production item.
Q. How important is the mounting?
A. We have found from experience that the actual accuracy of a mirror can become meaningless unless they are correctly mounted in a stress free environment. OS can mount and test optics to ensure that there is no distortion during mounting, in a clean room if required.
Q. Do you hold any stock to enable a shorter lead time?
A. Yes we hold a large stock of OAP ‘parents’ which if suitable for your requirements, would considerably reduce the delivery time.
Q. What coatings do you offer?
A. All commercially available coatings.