Abstract: An optical testing apparatus for use in non-destructive testing of optical omponents to evaluate their operational requirements. The optical component to be tested is mounted on a fixture that allows its accurate alignment and rotation so the entire surface area of the optical component can be scanned in discrete areas. A laser light source is positioned to illuminate the optical component with coherent light beams or rays. An aperture positioned in the light beam permits adjustment of the diameter of the light beam impinging on the optical component to be evaluated. Whenever an imperfection is present in the optical component a portion of the light rays illuminating the imperfection will be disarranged or scattered. Both the non-scattered and scattered light rays are gathered by means of pyroelectric detectors and their outputs are compared for obtaining an electrical signal that is proportional to the intensity of the scattered light caused by the imperfection.