Shear plates are ideally suited to determine the proper adjustment for a laser collimation system. They can also be used to measure wavefront radius of curvature, determine wavefront symmetry, measure the power of long-focal-length optics and in some cases analyze wavefront aberrations.
A collimator is a projector that images a reticle at a specific distance. Usually, imaging to infinity occurs at the wavelength 525 nm, but adjustment to finite distances or other wavelengths are also common and possible. Collimators are used in conjunction with test telescopes for angle measurement and angle adjustment.