Patent ID: 10197668

Abstract:
Laser radar systems include focusing optical systems having a retroreflector such as a corner cube that is translatable with respect to an objective lens. The retroreflector provides a selected retardance to an interrogation optical beam that is directed to a target as well as to a returned portion of the interrogation optical beam that is directed to a detection system. Typically, an input linearly polarized interrogation beam is returned by the retroreflector as a circularly polarized beam that is directed to the target. Returned beam portions from the target are coupled by the retroreflector to a detection system in a linear polarization that is orthogonal to that of the input linearly polarized optical beam. The retroreflector produces state of polarization changes based on retardance associated with total internal reflection from coated or uncoated optical surfaces. Retroreflector surfaces that are not to introduce retardance are coated with suitable zero or low retardance coatings.