Multi-spot collection optics

An apparatus for detecting optical radiation emitted from an array of spots on an object, the apparatus comprising:

• a plurality of light guides having respective input ends and output ends, with the input ends ordered in a geometrical arrangement corresponding to the array of the spots;
• relay optics, configured to collect and focus the optical radiation from the array of spots on the object onto the input ends such that each input end receives the optical radiation from a corresponding one of the spots;
• and
• multiple detectors, each detector coupled to receive the optical radiation from a respective output end of a respective one of the light guides.