Abstract: A method and system is disclosed for purposefully modifying the accessibility of information encoded upon an optical medium for indicating a state or history of the optical medium and/or a state or history of an item associated therewith. In one embodiment, the optical medium is purposefully damaged when the information is initially accessed so that upon subsequent access attempts of the information on the optical medium, a previous access of the information is detected by the purposefully induced errors. Thus, there is provided an effective technique for limiting illegal duplication and/or use of, e.g., software, movies, and music on compact disks and digital versatile disks. The present invention provides verification of persons and/or financial transaction cards during financial transactions. In another embodiment, a compact data storage device is disclosed having the approximate dimensions of a credit card that is capable of storing large amounts of data (e.g., 50-100 Megabytes).

Abstract: Data storage media for use with optical scanning machines are adapted to limit access to information stored thereon. Optical disks are used in an optical readout system of a computer to limit continual access to stored data by the optical readout system. A method is provided for limiting access to data stored in an optical media environment.

Abstract: The invention comprises a digital frequency generator particularly adapted for use with acousto-optical scanning devices, and particularly for such devices as for producing a scan or a raster scan or the like. The invention electronic circuitry includes a precision timing generator which is made up of a tapped delay line which feeds a multiplexor to produce an output pulse of any desired configuration. The output pulses are produced in a stream, but each pulse is produced individually.

Abstract: A single-crystal electro-optic modulator is described which positions a cubic temperature-stable bulk single crystal between two polarization plates rotated 90.degree. with respect to each other which are located between lensing means which focus divergent radiation emitted from an optical fiber into parallel rays for passage through the polarization means and the crystal and refocus the parallel rays a focal point and within the angle of acceptance of a return optical fiber.

Abstract: A system for tracking a randomly moving object using a laser beam and first and second beam steering assemblies. The steering assemblies pivot, respectively, about substantially perpendicular and intersecting X and Y axes and direct the laser beam along an R axis, which is perpendicular to the X axis and intersects the X and Y axes. Along the R axis, the laser beam is intercepted by a retroreflector, which is coupled to the moving object and which returns the laser beam to a quadrant detector via the steering assemblies. The quadrant detector generates an error signal representative of the object's movement relative to the X and Y axes, and this signal is transmitted to two motors which pivot the steering assemblies about the X and Y axes to reduce the error to zero. The system includes an interferometer to determine the distance of the object from a reference location. The first beam steering assembly includes two prisms which redirect the laser beam through three 90.degree.

Abstract: A system for tracking a random seam on a surface for the purposes of, for example, welding or inspecting the seam. The sensing assembly in the system comprises a laser and a scattered light detector. The beam from the laser is scanned across the seam via an acousto-optical deflector in the range of 170-2100 scans per second, thereby providing accurate tracking of the seam while allowing the system to move longitudinally along the seam in the range of 3.3 to 10 inches per second. The scanning width is reduced, or windowed, to decrease the amount of data received by the detector and the system's overall control system to allow the higher speeds in the range while maintaining the desired tracking accuracy by decreasing data processing time.

Abstract: A system for accurately controlling the movement of an object through a predetermined non-rectilinear path in a predetermined volume having X, Y and Z axes. The system uses three tracking laser interferometers rigidly positioned relative to the volume and a single retroreflector rigidly coupled to the object to control movement of the object non-rectilinearly through the volume along a predetermined path. Using two more tracking laser interferometers and an additional retroreflector rigidly coupled to the object, the system controls angular orientation of the object about one of the axes. Adding a sixth tracking laser interferometer and a third retroreflector to the object, the system can also control angular orientation about the other two axes. Each tracking laser interferometer comprises an interferometer and a tracking mirror which is pivoted to maintain the interferometer output beam on its associated retroreflector.

Abstract: An improved acousto-optic device and method featuring an acousto-optic element having an alkali metal oxide-tellurite glass composition comprising at least 92 wt % tellurium dioxide and one or more alkali metal oxides selected from the group consisting of sodium oxide and potassium oxide. A process for decreasing the acoustic attenuation of the aforementioned glass composition by annealing is also disclosed.

Abstract: An improved acousto-optic device and method featuring an acousto-optic element having an alkali metal oxide-tellurite glass composition comprising at least 92 wt % tellurium dioxide and one or more alkali metal oxides selected from the group consisting of sodium oxide and potassium oxide. A process for decreasing the acoustic attenuation of the aforementioned glass composition by annealing is also disclosed.

Abstract: Traveling acoustic waves, in an acoustooptic cell which exhibits an anisotropic diffraction mode, diffract a portion of polychromatic light passing through the cell. The acoustic waves are generated by electro-mechanical transducer means powered by electrical signals having a frequency component for each optical wavelength, and each frequency component can be varied over a bandwidth chosen such that light of optical wavelengths not associated with that frequency component is diffracted with an intensity a predetermined amount less than the intensity of the diffracted light of the optical wavelength associated with that frequency component. Each acoustic wave frequency component may be synchronized with the other frequency components such that the diffracted beams remain collinear throughout their scan, and the bandwidth of each frequency component can be chosen such that the angles of diffraction of light of all wavelengths are substantially equal.