Abstract: This invention relates to the modification of lasing medium surfaces, such as crystals, to reduce the internal reflections that contribute to amplified spontaneous emission (ASE) losses. A laser ablation treatment involves focusing an optical irradiation means on a target surface having desired ablation pattern and ablating the target surface according to the selected ablation pattern. A cross-hatch pattern on the target surface is secured by the target surface being mounted onto a precision motor driven translation stage and stepped throughout the desired ablation pattern. The optical irradiation means are oriented initially at 45.degree. to the target surface length and subsequently rotated by 90.degree..

Abstract: An imaging system responsive to focused laser light includes a focusing lens for focusing the laser light and a mirror having a reflective side, a non-reflective side, and a hole for passing a predetermined portion of the laser light from the focusing lens through the non-reflective side. A fiber probe excites and couples fluorescence from an analyte. The fiber probe has a fiber front face for receiving laser light through the hole and for directing the fluorescence to the reflective side of the mirror. Optical devices for imaging the portion of the fluorescence reflected by the mirror to form an image of the fiber front face are provided, as well as an optical stop having an aperture in the image plane of the imaging means for reducing undesired light from the imaging means before reaching a detector. The mirror is angled for directing substantially all fluorescence from the the fiber probe into the imaging means rather than back toward the fiber probe.

Abstract: A spatially resolved map of the eye's refractive characteristics are provided by measuring the eye's refractive characteristics on a point-by-point basis across the anterior surface of the eye. This spatially resolved refraction data may be obtained subjectively by providing a reference pattern and a measurement beam, by establishing a particular position on the cornea as the location to be measured and manipulating the orientation of the measurement beam at that measurement point to bring the measurement beam to a desired position relative to the reference image. When the patient indicates that the measurement beam is in the desired position relative to the reference pattern, the orientation of the beam is recorded as the refractive data for that measurement point and the process proceeds to another measurement point. This provides relatively rapid, physiologically accurate refractive data on a spatially resolved basis.

Abstract: Eye alignment is determined by producing a combined iris/retinal image by use of an imaging system. The relative position of the centroid of the pupil and various structures on the retina is indicative of the eye alignment. The eye alignment may be determined by comparing a combined iris/retinal image at the present time with a stored iris/retinal image at a past time. The imaging system may be a laser scanning ophthalmoscope.

Abstract: An alignment system for use with a keratoscope to form an eye measurement system uses a source of a light beam which is directed towards a cornea. A reflection from that beam is supplied to first and second quadrant detectors which are connected to circuits to generate an output when the cornea is properly aligned. Upon proper alignment, the system triggers the calculation of the cornea shape by the keratoscope.

Abstract: A hologram is used to project an image of a pattern similar to a placido upon the cornea of a subject. By viewing the reflection of the pattern in the subject's cornea, one may measure the curvature of the cornea. The use of the hologram in the keratometer system allows the pattern to be imaged at infinity, thereby minimizing any error which might otherwise result from incorrect assumptions about the cornea position.

Abstract: An apparatus for producing a tape superconductor of a compound superconductor type wherein the apparatus includes a first wire constructed of the superconducting compound material which is melted to form a bead. The bead is then wiped on a tape substrate to form a layer as the substrate is fed by the bead. Finally, the layer is cooled and a tape superconductor is formed.

Abstract: An input/output port for a lasing medium to minimize wavefront distortion of a coherent light beam is described. The input/output port includes an end surface integral the medium and a first port surface integral the end surface. The first port surface is substantially perpendicular to a plane normal to the longitudinal axis extending through the medium so that each ray of a beam of coherent electromagnetic radiation lying in a plane of a thickness of the beam may impinge on the port surface at a substantially equal angle with respect to reference planes normal to the port surface at the points of impingement.

Abstract: The temperature of a surface undergoing a radiation assisted thermally driven process is sensed by observation of the thermal emission from that surface and used to control the process. In a preferred embodiment, the blue edge of the thermal emission spectral distribution is detected to determine the surface temperature of a workpiece during a process such as laser-assisted chemical vapor deposition, and used to control this temperature. The temperature measuring system has means for focusing workpiece thermal emission and defining the field of view, a spectrometer to separate shorter wavelength light from other spectral components of the thermal emission, and a photon-counting system to detect the shorter wavelength light and generate a surface temperature signal. Systems to determine surface temperature at a spot and along a line have an optical prism to disperse the thermal emission into component wavelengths, and a multichannel photon-counting detector comprised of an intensified photodetector array.

Abstract: A laser peening apparatus and method for peening a workpiece utilizing a laser beam is described. The system includes a foil aligned with a surface of the workpiece to be peened and lasing the aligned foil surface. The foil absorbs energy from the beam and a portion of the foil vaporizes, which creates a hot plasma within the foil. The plasma creates a shock wave which passes through the foil and peens the workpiece surface.

Abstract: The wetting angle of a bead, such as a welding bead, is detected and controlled by a feedback operation. In particular, one or more optical profiler heads are used to detect the wetting angle along the edge of a bead. If the wetting angles differ from a preferred value, a feedback control system adjusts one or more weld parameters in order to bring the wetting angles to a desired value. If the wetting angle obtains a value which makes the weld joint completely unacceptable, an alarm condition may be activated. The detection of the bead wetting angles may be provided by two optical profiler heads, each head tracking a corresponding one of the edges or sides of the bead so as to provide information from which a corresponding wetting angle may be obtained.

Abstract: Multiple light detection channels are introduced into a flying spot optical triangulation ranging system to increase the speed of acquiring range values. A laser beam is rapidly swept across a surface by a beam deflector. Each fiber optic channel can receive light only from a different point along a line at the intersection of the swept beam with the surface. The receiver channels are duplicated and separate detectors generate signal pulses at times that are a function of range to the surface. These are processed in parallel to calculate N range values per beam sweep, where N is the number of channels.

Abstract: Automated grinding is performed using a tracking means having a sufficient field of view to locate edges to be processed and using a high resolution profiler in order to provide grinding information for calculation of the amount of material which should be removed from the workpiece. Those sections of the workpiece not requiring additional grinding may be traversed at a high speed in order to improve productivity. A process control computer receives grinding information from the tracking means and high resolution profiler and uses it to control a manipulator to adjust the travel speed of the grinder, force with which a grinder is applied, position of the grinder, and/or speed of rotation of the grinder in order to remove the correct amount of material from a workpiece. The technique is especially advantageous in removing excess material, burrs, nicks, chips and other minor irregularities in workpieces. A second profiler may be used to check that the grinder has properly ground portions of the workpiece.

Abstract: High speed readout is achieved in a triangulation ranger by a coded aperture light detector which provides a direct digital representation of a range or height position. A light spot reflected from the surface is optically spread into a line segment so it can be shared among a number of light detection channels. The line of light falls on a coded aperture in front of a segmented fiber optic bundle and the light transmitted by each channel is led to a separate photomultiplier or solid state detector. Every coded channel is constructed to give one bit of the digital address of the range position, and a reference light value is obtained from another channel. Background and secondary reflections may be filtered out by focusing light scattered from the surface to a spot and passing it through a slit aperture oriented in the plane of triangulation before being spread to a line segment.

Abstract: An optical sensor head has deep, pitched grooves or screw threads in the walls of the gas channel, and a gas flow swirled along the grooves to protect optics against atmospheric debris and moving particles such as is generated by an industrial process. The grooves are pitched to support swirling motion of the gas. Use of swirled flow increases allowable flow velocity and diverts incoming particles toward the channel walls. The windows of an optical profiler, for instance, are protected against the smoke and weld spatter created by a metal-inert-gas welding torch.

Abstract: Automated grinding is performed using a tracking means having a sufficient field of view to locate edges to be processed and using a high resolution profiler in order to provide grinding information for calculation of the amount of material which should be removed from the workpiece. Those sections of the workpiece not requiring additional grinding may be traversed at a high speed in order to improve productivity. A process control computer receives grinding information from the tracking means and high resolution profiler and uses it to control a manipulator to adjust the travel speed of the grinder, force with which a grinder is applied, position of the grinder, and/or speed of rotation of the grinder in order to remove the correct amount of material from a workpiece. The technique is especially advantageous in removing excess material, burrs, nicks, chips and other minor irregularities in workpieces. A second profiler may be used to check that the grinder has properly ground portions of the workpiece.

Abstract: Feed process control is accomplished using an optical profiler to determine the height, width, and cross sectional area of a bead produced by a bead producing tool. Feedback control of the height, width, and/or area is obtained by modifying various parameters of the bead producing tool. If the bead producing tool is a welding torch, the parameters may include the weld torch voltage, weld torch current, wire feed rate, and the speed of travel of the torch across the workpiece or workpieces. If the bead producing tool is a sealant or glue gun, the parameters may include the pressure of the sealant or the glue supplied to the sealant or the glue gun, the size of an adjustable nozzle orifice of the sealant or the glue gun, and the speed of travel of the sealant or the glue gun along the surface of the workpiece.

Abstract: Two identical prism telescopes each comprised of a train of right angle prisms are used to spread out a laser beam to the maximum width of an acousto-optic cell and reconverge the beam to original dimensions. The first telescope increases the beam size along one dimension while bending the beam through 90.degree.. The second telescope reduces the beam size and multiplies the angle of deflection while redirecting the beam through another 90.degree.. There is a 180.degree. fold in optical path and this configuration is compact, has low losses, and is easy to mount and align.

Abstract: An optical technique for determining remotely movement of a movable point such as a point on a robotic end effector moving in three-dimensional space, based on observation of moving fringe patterns. In a preferred embodiment, at least one moving interference fringe pattern is projected from at least one spaced pair of coherent point light sources, having different frequencies, and a photodetector responsive to illumination at the movable point is employed to count fringes as they cross the movable point. The difference frequency between the light sources causes the fringes to move at a known rate to provide sense-of-direction information in that this results in the detector output having a frequency component which reflects point motion. Full three-dimensional location is obtained by observing three independent fringe patterns in three independent directions. Such a set of patterns can be produced by as few as three point sources operating at three different frequencies.

Abstract: A flying spot system uses a laser beam scanned in X and Y directions to provide surface profile information. The beam is applied to a surface under test and the time interval between the beginning of the sweep and the appearance of the beam image through an aperture is determined. This time interval is indicative of the beam angle which, through optical triangulation, is used to determine the surface height. A scan-descan arrangement and a plate with a small aperture are used to isolate a light detector from background light.