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Patents

Low-Cost Fiber Optic Pressure Sensor
Sang K. Sheem
U.S. Patent 6,738,537 B2
May 18, 2004
The cost of fabricating a fiber-optic pressure sensor is reduced by making the membrane of the sensor in a nonplanar shape. The sensor design calls for the nonplanar membrane to become a part of an airtight cavity, which makes the membrane resilient because of the cavity’s air-cushion effect. Such nonplanar membranes are easier to fabricate and attach.

Short Pulse Laser Stretcher–Compressor Using a Single Common Reflective Grating
Gaylen V. Erbert, Subrat Biswal, Joseph M. Bartolick, Brent C. Stuart, Steve Telford
U.S. Patent 6,739,728 B2
May 25, 2004
This invention provides an easily aligned, all-reflective, aberration-free pulse stretcher–compressor in a compact geometry. The stretcher–compressor device is a reflective, multilayer dielectric that can be used for high-power chirped-pulse amplification material processing applications. The device is constructed with a reflective grating element that receives a beam for stretching of laser pulses in a stretcher beam path. The element also receives stretched amplified pulses to be compressed in a compressor beam path through the same reflective, multilayer dielectric-diffraction grating. The stretched and compressed pulses are interleaved around the grating element to provide the desired number of passes in each respective beam path.

Shape Memory Polymer Actuator and Catheter
Duncan J. Maitland, Abraham P. Lee, Daniel L. Schumann, Dennis L. Matthews, Derek E. Decker, Charles A. Jungreis
U.S. Patent 6,740,094 B2
May 25, 2004
An actuator system is provided for acting on a material in a vessel. The system includes an optical fiber and a shape-memory polymer material operatively connected to the optical fiber. The shape-memory polymer material is adapted to move from one shape for moving through the vessel to a second shape for acting on the material.

Apparatus for Etching or Depositing a Desired Profile onto a Surface
Michael C. Rushford, Jerald A. Britten
U.S. Patent 6,740,194 B2
May 25, 2004
An apparatus and method for modifying the surface of an object by contacting the surface with a liquid processing solution using the liquid applicator geometry and Marangoni effect (surface tension gradient-driven flow) to define and confine the dimensions of the wetted zone on the object surface. In particular, the method and apparatus involve contouring or figuring the surface of an object using an etchant solution as the wetting fluid and using real-time metrology (for example, interferometry) to control the placement and dwell time of the wetted zone locally on the object’s surface, thereby removing material from the object’s surface in a controlled manner. One demonstrated manifestation is the deterministic optical figuring of thin glasses by wet chemical etching using a buffered hydrofluoric acid solution and the Marangoni effect.

Gamma Watermarking
Muriel Y. Ishikawa, Lowell L. Wood, Ronald W. Lougheed, Kenton J. Moody, Tzu-Fang Wang
U.S. Patent 6,740,875 B1
May 25, 2004
A covert, gamma-ray signature is used as a watermark for property identification. This new watermarking technology is based on a unique digital signature from tiny quantities of gamma-ray-emitting radioisotopic materials, generally covertly emplaced on or within an object. This digital signature may be readily recovered in the future by placing a sensitive, high-energy-resolution, gamma-ray detecting instrument over the watermark, whose location may be known only to the object’s owner; however, the signature is concealed from all ordinary detection means because its exceedingly low level of activity is obscured by the natural radiation background, including the gamma radiation naturally emanating from the object itself. The watermark is used for object-tagging to establish object identity, history, or ownership. Thus, it may serve as an aid to law enforcement officials in identifying stolen property and prosecuting theft. Gamma watermarking is a highly effective and low-cost way to immediately identify most types of property.

Coherent White Light Amplification
Igor Jovanovic, Christopher P. J. Barty
U.S. Patent 6,741,388 B2
May 25, 2004
This system for coherent, simultaneous amplification of a broad spectral range of light includes an optical parametric amplifier and a seed pulse source. A first angular dispersive element is connected to the seed pulse source. A first imaging telescope is connected to the first angular dispersive element and to the optical parametric amplifier. A pump pulse source is connected to the optical parametric amplifier. A second imaging telescope is connected to the optical parametric amplifier and a second angular dispersive element is connected to the second imaging telescope.

Precision Gap Particle Separator
William J. Benett, Robin Miles, Leslie M. Jones II, Cheryl Stockton
U.S. Patent 6,746,503 B1
June 8, 2004
This system for separating particles entrained in a fluid includes a base with a first and second channel. A precision gap connects the two channels. The precision gap size allows small particles to pass from the first channel into the second channel but not large particles. A cover is positioned over the base unit, the first channel, the precision gap, and the second channel. A port directs the fluid containing the entrained particles into the first channel. An output port directs the large particles out of the first channel. A port connected to the second channel directs the small particles out of the second channel.

Carbon Nanotube Coatings as Chemical Absorbers
Thomas M. Tillotson, Brian D. Andresen, Armando Alcaraz
U.S. Patent 6,749,826 B2
June 15, 2004
Carbon nanotubes are used to collect airborne or aqueous organic compounds. Exposure of carbon-nanotube-coated disks to controlled atmospheres of chemical warfare– (CW–) related compounds provide superior extraction and retention efficiencies compared with commercially available airborne organic-compound collectors. For example, the carbon-nanotube-coated collectors were four times more efficient when concentrating dimethylmethylphosphonate (DMMP), a CW surrogate, than Carboxen, the optimized carbonized polymer for CW-related vapor collections. In addition to DMMP, the carbon-nanotube-coated material possesses high collection efficiencies for the CW-related compounds diisopropylaminoethanol, and diisopropylmethylphosphonate.

Optical Distance Measurement Device and Method Thereof
Mark W. Bowers
U.S. Patent 6,750,960 B2
June 15, 2004
A system and method to efficiently scan a target and obtain distance measurements. A light source provides an optical beam, and a frequency source modulates the beam. The modulated optical beam is transmitted to an acoustooptical deflector that changes the angle of the optical beam in a predetermined manner to produce an output for scanning the target. A detector receives the reflected or diffused light from the target and transmits it to a controller, which is configured to calculate the distance to the target as well as the measurement uncertainty in calculating the distance to the target.

Method for Distinguishing Multiple Targets Using Time-Reversal Acoustics
James G. Berryman
U.S. Patent 6,755,083 B2
June 29, 2004
This time-reversal acoustics method for distinguishing multiple targets uses an interactive process to determine the optimal signal for locating a strongly reflecting target in a cluttered environment. An acoustic array sends a signal into a medium and then receives the returned reflected signal. This returned reflected signal is then time-reversed and sent back into the medium again and again, until the signal being sent and received is no longer changing. At that point, the array has isolated the largest eigenvalue and eigenvector combination and has effectively determined the location of a single target in the medium (that is, the one that is most strongly reflecting). Once the largest eigenvalue and eigenvector combination has been determined, the location of other targets is determined. Instead of sending back the same signals, the method sends back the time-reversed signals. Half of these signals will also be reversed in sign. Various possibilities exist for choosing which half to do sign reversal. The most obvious choice is to reverse every other one in a linear array or in a two-dimensional checkerboard pattern. Then, a new send-and-receive, send-time reversed, and receive iteration can proceed. Often, the first iteration in this sequence will be close to the desired signal from a second target. In some cases, procedures must be implemented to ensure the returned signals are orthogonal to the first eigenvector.

Lightweight Flywheel Containment
James R. Smith
U.S. Patent 6,756,091 B1
June 29, 2004
A lightweight flywheel containment absorbs the energy of a flywheel structural failure. It is composed of layers of various materials that act as a vacuum barrier, momentum spreader, energy absorber, and reaction plate. In a demonstration, the flywheel containment structure had an aerial density of less than 6.5 grams per square centimeter and contained carbon fiber fragments with a velocity of 1,000 meters per second. The flywheel containment structure may be composed of an inner high-toughness structural layer, an energy-absorbing layer, and an outer support layer. An optional layer of impedance-matching material may be used.

Oxidation Preventative Capping Layer for Deep-Ultra-Violet and Soft X-Ray Multilayers
Shon T. Prisbrey
U.S. Patent 6,759,141 B2
July 6, 2004
This invention uses iridium and iridium compounds as a protective capping layer on multilayers that have reflectivity in the deep ultraviolet to soft-x-ray regime. The iridium compounds can be formed either by direct deposition of the iridium compound from a prepared target or by depositing a thin layer (for example, 0.5 to 5 nanometers) of iridium directly on an element. The deposition energy of the incoming iridium is sufficient to activate the formation of the desired iridium compound. The compounds of most interest are iridium silicide and iridium molybdenide.

Application of Yb:YAG Short Pulse Laser System
Gaylen V. Erbert, Subrat Biswall, Joseph M. Bartolick, Brent C. Stuart, John K. Crane, Steve Telford, Michael D. Perry
U.S. Patent 6,760,356 B2
July 6, 2004
A diode-pumped, high-power (at least 20-watt), short-pulse (up to 2-picosecond), chirped-pulse amplified laser using ytterbium-doped yttrium aluminum garnet (Yb:YAG)) as the gain material is used for material processing. Yb:YAG is the gain medium for both a regenerative amplifier and a high-power four-pass amplifier. A single common reflective grating optical device stretches pulses for amplification and recompresses amplified pulses before being directed to a workpiece.

Awards



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UCRL-52000-04-9 | September 3, 2004