Abstract: Variable shear A.C. interferometer based on a rotating radial grating. Light is passed through the rotating radial grating to produce multiple sidebands diffracted at various angles. These multiple sidebands produce overlapping (sheared) images of the input wavefront at a detector plane causing intensity variations proportional to the phase difference between the sheared wavefronts. An array of detectors is positioned to monitor the images on the detector plane and the outputs of each are processed to obtain the local slope of the wavefront averaged over each detector. From this data, complete wavefront slope information in one direction (X) can be obtained. By providing a second interferometer to make slope measurements in the Y direction, complete information can be obtained from which the entire input wavefront can be reconstructed.

Abstract: A cutting implement formed from a substrate of carbide, or other hard substance, bonded to a polycrystalline layer which serves as the cutting portion of the implement. The interface between the substrate and polycrystalline layer is defined by surface topography with radially spaced-apart protuberances and depressions forming smooth transitional surfaces.

Abstract: A wavefront sensor for detecting the slope of an input wavefront. A surface acoustic wave reflective diffraction grating is positioned at a focal point of the wavefront, and generates surface acoustic waves at two primary frequencies f.sub.1 and f.sub.2. The reflective diffraction grating produces a first AC shearing interferogram between two like diffraction orders generated by the f.sub.1 and f.sub.2 surface acoustic waves. A photodetector array is positioned to detect the shearing interferogram at a two dimensional array of zones, and the phase of the output signal for each zone is representative of the local slope of the wavefront in the direction of shearing, thus producing the slope in one direction. Complete two dimensional wavefront slope information is obtained by shearing the wavefront in a second orthogonal direction in substantially the same manner utilizing a second surface acoustic wave diffraction grating and a second photodetector array.

Abstract: An integrated wavefront compensator for an active optics system in which the components for detecting distortions in a wavefront and the components for correcting the detected wavefront distortions are integrated into one unit. The parallel processing channels of the compensator are fabricated simultaneously using simple, solid state components.

Abstract: A relatively simple wavefront sensor is constructed with an astigmatic optical system which focuses an indicent wavefront to x and y focal planes, with the x and y focal planes being relatively displaced along the optical axis because of the astigmatic nature of the optical system. An x modulation reticle is positioned at the x focal plane, and an x drive tuning fork drives the x modulation reticle in linear oscillation at a frequency f.sub.x to modulate the wavefront thereat. A y modulation reticle is positioned at the y focal plane, and a y drive tuning fork drives the y modulation reticle in oscillation, substantially perpendicular to the direction of oscillation of the x modulation reticle, at a frequency f.sub.y, different from the frequency f.sub.x, to also modulate the wavefront thereat. A detector array then receives the modulated wavefront, with each detector in the array receiving and detecting a different zone of the incident wavefront.

Abstract: An incremental slope wavefront sensor having an optical system which focuses an incident wavefront to a focal point. A novel modulation reticle is positioned at the focal point, and is driven in linear oscillation along a single axis. The modulation reticle has a modulation pattern formed thereon by alternating triangular light transmissive areas and inverted triangular light reflective areas. A first detector array detects the wavefront which has passed through the transmissive areas and diverged from the focal point in a two dimensional array of zones. A second detector array detects the wavefront which has been reflected by the reflective areas and diverged from the focal point in a two dimensional array of zones. The output signals from the first and second detector arrays for each corresponding zone are differentially combined to form a differential output signal for each zone.