Patent ID: 9702983
Date: 2017-07-11
CPC Classifications: G01J,G01N,G01T,H01J

Claim:
1. An apparatus for detecting optical radiation emitted from an array of spots on an object resulting from multiple excitation beams incident on the 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 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; multiple detectors, each detector coupled to receive the optical radiation from a respective output end of a respective one of the light guides; and an alignment unit configured to monitor changes in pitch and rotation angle of the array of spots resulting from changes in energy of the multiple excitation beams, wherein the changes in rotation angle occur about an axis normal to the surface of the object, wherein the alignment unit is further configured to, in response to detecting the changes, generate signals indicative of an alignment of the plurality of light guides with the array of spots.