Abstract: An improved wavefront sensor for characterizing phase distortions in incident light including optical elements that spatially sample the incident light and form a dispersed spot with a fringe pattern corresponding to samples of the incident light. An imaging device captures an image of the dispersed spot with said fringe pattern formed by said optical elements. And an image processor that analyzes the spectral components of the fringe pattern of a given dispersed spot to derive a measure of the local phase distortion without ambiguity in the corresponding sample of incident light. The optical elements may comprise refractive elements, diffractive elements or a combination thereof (such as a grism). The wavefront sensor may be part of an adaptive optic system (such as a large-aperture space telescope) to enable the measurement and correction of large phase steps across adjacent mirror segments of a deformable mirror.

Abstract: A panoramic imaging system is formed from select configurations of micro-optic multiplets (MOM) comprised of two microlens modules (MLM). The MLMs themselves are formed from arrays of microlenses. The present panoramic imaging system is characterized by the two MLMs configured on concentric approximately spherical surfaces. The optic axis of each of the microlenses is tilted slightly with respect to its neighbor to allow for proper alignment of images to form a single primary image on a substantially spherical global image surface.

Abstract: A variety of optical systems can be formed from select configurations of micro-optic multiplets (MOM) comprised of two or more microlens modules (MLM). The MLMs themselves are formed from planar arrays of microlenses. An optical system configured in accordance with the present invention forms a single primary image, together with a set of images transversely displaced from an optic axis and is characterized by the property that the image distance and the object distance move in the same direction, in stark contrast to known lens systems. For example, when an object distance decreases, the corresponding image distance also decreases with the present optical system.

Abstract: An improved two-dimensional optical centroid processor ("OCP") wavefront sensor is described in which a scanning mirror 146 scans the wavefront of input light 130 to provide a scanned beam 148 (i.e. a portion of the wavefront). The scanned beam 148 is focused on an OCP 168 filter comprising four rows of mask cells. The filtered light emanating from the cells impinges on one-dimensional photodetector devices 192, 198, 202, 206 (i.e. photodetector rows). Thus, the scanning of the wavefront by the scanning mirror provides two-dimensional measurement while employing one-dimensional photodetector devices. Each of the photodetector devices provides an output to a ratio calculator 201 which is used to correct the tilt in the wavefront by driving a deformable mirror (not shown).

Abstract: An optical system that records images that travel through a turbulent atmosphere to a camera on a moving platform is designed to sense image distortions in a first segment of the image and to apply a set of correction signals to a segment of a deformable mirror that corresponds to the portion of the image that is detected. In a closed-loop embodiment, the corrected subimage is followed across the aperture, with successive corrections being applied sequentially to each of a set of segments at the time when that segment is reflecting the subimage in question. Consecutive subimages follow the same procedure. Corrected subimages are reflected off the deformable mirror to a detector array. At intervals, a frame's worth of data may be read out of the detectors and stored.

Abstract: An improved optical centroid processor wavefront sensor is described in which an image is optically impinged on a plurality of mask arrays. A group of mask arrays, having a coarse dependant function, filters light onto corresponding photodetector arrays. The output of the photodetectors provide a coarse signal indicative of spot displacement over an increased tilt dynamic range. Another group of mask arrays, having a fine dependant function, filters light onto corresponding photodetector arrays. The output of the photodetectors provide a fine signal indicative of spot displacement with an increased accuracy. The coarse and fine signals may be employed by a deformable mirror to correct aberrations in a light beam wavefront.

Abstract: A wavefront sensing and compensating system for detecting and correcting for distortion in light wavefronts is described in which the wavefront is divided into a plurality of subapertures and light intensified and imaged as spots of light from each subaperture onto a detector array. The individual detector elements of the array form a plurality of electrical signals proportional to the local divergence of the vector gradient field (.gradient..sup.2 .phi.). This .gradient..sup.2 .phi. signal after interfacing or reconstruction is applied to corrective mirrors which may be of the deformable or membrane type.

Abstract: A wavefront sensor for detecting distortion in light wavefronts is described in which the wavefront is divided into a plurality of subapertures and light amplified or intensified and imaged as spots of light from each subaperture onto a filter mask. The filter mask encodes a predetermined function of the spot intensity distributor onto the light intensity of the spot transmitted through the filter. For spot centroid calculation, the function is linearly variable. Mask embodiments include linearly varying alternate opaque and transparent chevrons, electronically variable chevrons, and quadratically varying chevrons.

Abstract: In an electrostatic copier of the type which utilizes a liquid developer for developing an electrostatic latent image formed on a copy sheet as a result of which the copy sheet becomes wet, there is provided improved apparatus for drying the wet copy sheet. The drying apparatus includes a movable belt, made of a strip of imperforate heat conductive material, for transporting the wet copy sheet in a predetermined path of travel through the drying station of the copier. The drying apparatus also includes a cover for deflecting air which is normally utilized for drying purposes, away from a portion of the belt so as to form first and second drying regions in the path of travel of the wet copy sheet. The drying apparatus additionally includes means for heating the moving belt at the first drying region, for urging liquid developer carried by the wet copy sheet towards the surface of the same which is disposed out of contact with the moving belt.