I have the following problem. I have a sensor with 1mm diameter and I need to have 500 urad (microradian) field of view. If I understand correctly, that would generally mean that I need to use 2meter focal length. However, I have 20cm space. It is acceptable to defocus the image if necessary. Can I achieve the required FOV for this sensor and distance at the receiver by using a combination of two or more lenses?

Thank you!


What about folding your optical path with mirrors?

I don't know a good way to sketch it, but imagine adding 4 mirrors in the optical path. The mirrors arranged in two pairs roughly facing each other, but slightly angled and offset so that the light zig-zags between the mirrors. So, the light enters the lens, and is reflected back-and-forth between the 4 mirrors before hitting the detector.

This results in 5 passes of the light, which brings your length down to 20 cm.

  • $\begingroup$ Oh, that deserves a thought. I was thinking for a two mirror system. Thank you! I will still wait to see if some lens approach will be proposed. $\endgroup$ – D. K. Mar 22 '18 at 2:02

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.