Curvature and focal length measurements using compensation of a collimated beam

A simple method for measuring the radius of curvature of a spherical surface using compensation of a collimated beam is described. The same method can also be used for the determination of the focal length of the collimating lens employed. Results of the measurements using this technique are presented. Investigations on the achievable accuracies and the proper choice of parameters are carried out and the results discussed. © 1991.