Bell Telephone Laboratories

At&t Bell Laboratories

Other

Cornell Research Foundation Inc.

Chandra K Patel

Van-Tran Nguyen

Andrew C Tam

Erich Gornik

Obert R Wood, Ii

Nils A Olsson

Theodoor Charlouis Damen

Ping K Tien

Theodore H Geballe

Thomas J Bridges

Albert R Strnad

Aly H Dayem

Theodoar Charlouis Damen

Earl D Shaw

David B Karlin

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.

Laser surgical system

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.

High speed analog-to-digital converter

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.

Free-electron amplifier device with electromagnetic radiation delay

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.

Method for shelling of nuts with a laser beam

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. Two conditions are shown to exist that relate pulse duration, beam size, and various material parameters, observation of which results in optimization of the sensitivity of the method, and the sensitivity is typically highest for pulses having duration of about 10.sup.-7 sec-10.sup.-4 sec.

Optoacoustic spectroscopy of condensed matter in bulk form

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. The method is applicable to liquids, solids suspended in liquids, gels, continuous or discontinuous solid films, powders, monolayers of strongly absorbing atoms, surfaces, and layerlike distributions of absorbing atoms within an essentially transparent matrix. Possible choices of probe radiation are not only the conventional ones of visible, near-UV, and near-infrared electromagnetic radiation, but also, for instance, X-rays, vacuum UV, and infrared, and matter beams, such as electron, ion, or neutral atom beams. Typical means for detecting the ultrasonic signal are ultrasonic bulk wave or surface wave transducers. For sufficiently short probe pulses, the amplitude of the ultrasonic signal is directly proportional to the absorption of the layer material at the frequency of the probe radiation, but longer pulses, such as, for instance, are obtained from mechanical choppers, can be used also. Apparatus is disclosed that minimizes interference with the measurement due to scattered light and transducer ringing, and that permits the measurement of fractional absorption down to 10.sup.-6 or less.

Optoacoustic spectroscopy of thin layers

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.

Epitaxial growth of superconductors such as Nb.sub.3 Ge superconductors

The invention relates to a high-power tunable infrared source employing a four-photon mixing process, with three input lasers, in which process the output power is resonantly enhanced by exciton states in the conversion medium.

Tunable infrared and far-infrared source by four-photon mixing

An optical polarization rotator is developed for use with infrared radiation using a nonlinear, two-photon interaction in a solid medium. The mechanism employed is resonance dispersion, where the sum frequency of an infrared beam to be rotated and a visible control beam is close to the frequency of a two-photon transition of exciton states, thereby producing different amounts of dispersion for the two orthogonal components of the linearly polarized infrared beam. The result of a phase difference between the two components is a rotation of the plane of polarization of the infrared beam.

Growing community of inventors

Summit, NJ, United States of America

Chandra K Patel