Abstract: A laser surgical instrument uses a CO.sub.2 laser source and an articulated arm structure to maintain single mode transmission of a 10.6 .mu.m beam to probe. In one configuration, high power is maintained for photo-transection and/or photocauterization. A second probe embodiment introduces other degrees of functionality such as aspiration, irrigation and internal viewing. Internal illumination is achieved by using the sheaths of quartz waveguides to transmit visible light while the laser beam is propagated internally in the waveguide structure.

Abstract: An analog-to-digital converter using a frequency tunable laser having output radiation of a frequency determined by the input voltage to the laser is described.

Abstract: In the interest of increased efficiency and gain of free-electron amplifier devices, means are provided for retarding electromagnetic radiation in such devices. This permits an electron beam pulse to catch up with a pulse of electromagnetic radiation and thus to interact repeatedly with electromagnetic radiation. Retarding means may be implemented, e.g., as one or several waveguides having suitable diameter and length; alternatively, resonant filters consisting essentially of wire meshes can be used.

Abstract: The removal of shells from hard shelled nuts, particularly macadamia nuts, is accomplished by rotating the nut in the path of a high power cw laser beam, such as a CO.sub.2 laser beam, so as to burn a path around the shell which separates the shell into parts which can readily be removed from the nut. A low power laser beam of a wavelength for which the nut shell and underlying nut meat have substantially different reflectivities, such as a helium-neon laser beam, is arranged to strike the nut collinearly with the high power beam. When the nut meat is exposed as the path in the shell is burned away, the intensity of the low power beam light which is reflected by the nut increases, and this increase is detected to give an indication of the completion of the shell burning operation.

Abstract: Method and apparatus for high-sensitivity (.alpha..ltorsim.10.sup.-6 cm.sup.-1) optoacoustic (OA) spectroscopy of substantially transparent bulk condensed matter. Part of the sample to be investigated is irradiated by pulses of radiation, typically from a pulsed dye laser. The small amount of energy absorbed by the sample causes thermal expansion of the irradiated region, resulting in cylindrical stress waves being radiated from that region. These stress waves can be observed with appropriate detection means at a location remote from the source. The method is applicable to essentially transparent liquids, and solids, and to absorptive solids suspended in liquids, and the like. Possible choices of probe radiation are not only the conventional ones of visible, near UV, and near infrared electromagnetic radiation, but also, for instance, .gamma.-rays, x-rays, vacuum UV, and far infrared.

Abstract: Method and apparatus for high-sensitivity optoacoustic (OA) spectroscopy of condensed matter in thin layer form. The layer to be investigated is to be in intimate contact with a solid substrate that is essentially transparent to the probe radiation, and that is capable of transmitting ultrasonic vibrations. Intermittent probe radiation, focused to a diameter typically 10.sup.-3 -1 cm when incident on the layer, cause local heating and dimensional change in the irradiated region of the layer. The dimensional change of that region causes deformation of the adjacent substrate material, the irradiated layer region thereby becoming a source of ultrasonic waves that are spreading out in the substrate from the source region, and which can be observed with appropriate detection means at a location remote from the source.

Abstract: Nb.sub.3 Ge, Nb.sub.3 Al and Nb.sub.3 Si are prepared in A15 structures at the exact stoichiometric ratio with epitaxial growth on selected substrates. The phase diagrams of the materials are altered by this technique and only the A15 phase is stable at the stoichiometric ratios thus permitting attainment of higher and sharper transition temperatures.