Portfolio News and Webcast

High Velocity Laser Accelerated Deposition: Coatings with Exceptional Corrosion Resistance & Extreme Interfacial Bond Strength by Joe Farmer, LLNL scientist

You will hear about an innovative new deposition technique for creating high performance protective coating with unparalleled interface strengths and corrosion resistance. This technology won a <a href="http://www.rdmag.com/award-winners/2012/08/corrosion-resistance-achieve… R&D 100 Award</a>.

Lasers and Optics Technologies

Livermore Lab researchers have developed a new EUV target design that replaces liquid tin droplets with tin microbeads embedded in a low Z tamping fluid. The use of low Z liquid tamped targets can solve several problems that are currently faced by the industry. It can increase the total operational uptime from 80% to close to 100%. It can simplify EUV source design and reduce operating costs by eliminating the need for some major components and their associated maintenance requirements.

The new LLNL technique works by transiently removing and trapping concrete or rock surface material, so that contaminants are confined in a manner that is easy to isolate and remove. Our studies suggest that 10 m2 of surface could be processed per hour. The technique easily scales to more surface/hr.

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Livermore Lab researchers have developed two new methods for improving the efficiency of laser drilling. The first method is based on multi-pulse laser technology. Two synchronized free-running laser pulses from a tandem-head Nd:YAG laser and a gated CW laser are capable of drilling through 1/8-in-thick stainless-steel targets at a standoff distance of 1 m without gas-assist. The combination of a high-energy laser pulse for melting with a properly tailored high-intensity laser pulse for liquid expulsion results in the efficient drilling of metal targets. The improvement in drilling is due to the recoil pressure generated by rapid evaporation of the molten material by the second laser pulse.

Livermore Lab's SBC grating optics benefit from the combination of the following key technologies:

  • LLNL proprietary optical coating designs utilizing >100 thin film layers – enables ultra-low-loss, ppm transmission levels through the coating, high diffraction efficiency, and large bandwidth.
  • LLNL proprietary dispersive surface relief structure design – perfectly impedance matched to the thin film stack for optimum optical performance.
  • Ability to fabricate dispersive surface relief structure and advanced optical thin film coating on superior thermally conductive materials such as silicon and silicon carbide.
  • LLNL proprietary processing techniques permitting the fabrication of optimum optical design.

LLNL researchers have invented a method for scaling the average power of high-energy solid-state lasers to high values of average output power while maintaining high efficiency. This method combines the gas-cooled-slab amplifier architecture with a pattern of amplifier pumping and extraction that is new to high-energy pulsed lasers, in which pumping is continuous and in which only a small fraction of the energy stored in the amplifier is extracted on any one pulse. Efficient operation is achieved by propagating many pulses through the amplifier during each period equal to the fluorescence decay time of the gain medium, so that the preponderance of the energy cycled through the upper laser level decays through extraction by the amplified pulses rather than through fluorescence decay…

LLNL researchers have developed a method in which a sleeveless photonic crystal optical fiber cane can be fabricated. A set of glass canes and capillaries, doped or un-doped, are stacked into a hexagonal pre-form. A piece of outer tube which is much shorter than the pre-form, but longer than the "hot zone" of a draw tower furnace, is placed around the pre-form on either end, and crimped to the preform near the outer edge. A photonic crystal fiber pre-form now exists in which the two ends of the pre-form have outer tubes holding the shape of the photonic crystal stack, while the central region of the preform is sleeveless, and takes the shape of the photonic crystal stack which need not be hexagonal and may be arbitrary.

The photonic crystal pre-form is then lowered into a…

As diode pumped solid state lasers (DPSSL) become more common there is a need to drive these pump diode arrays in a compact, efficient and cost-effective manner. The LLNL system for controlling high current laser diode arrays is an integrated system for meeting the needs of driving laser diode arrays in a DPSSL. The system is comprised of technologies required to control the DPSSL that includes individual laser diode drivers, a method of communicating with those drivers, and a method of controlling the pulse shape of each diode driver. LLNL has demonstrated how these subsystems are put together in a system that also includes methods of mounting, cooling and controlling high average power diode arrays used for the purpose of pumping DPSSLs.

LLNL has developed several MLD grating technologies that extend the state of the art in overall laser optical power handling capability. LLNL MLD grating optics are the convolution of the following key technologies:

  1. Optical coating designs utilizing >100 thin film layers - enables ultra-low-loss, ppm transmission levels through the coating, high diffraction efficiency, and large bandwidth.
  2. Dispersive surface relief structure design - perfectly impedance matched to the thin film stack for optimum optical performance.
  3. Ability to fabricate dispersive surface relief structure and advanced optical thin film coating on superior thermally conductive materials such as silicon and silicon carbide.
  4. Processing techniques permitting the fabrication…

LLNL researchers have developed a method for fabricating active or passive optical glass components, non-optical glass components, and/or glass sensors with custom material composition profiles in 1-, 2-, or 3-dimensions. In this method, DIW additive manufacturing technique is used to print filaments of a rheologically-tuned ink--containing a glass forming species--into a loosely bound, amorphous, low density form (LDF), analogous to a green body in ceramics. DIW inks of different compositions may be blended inline at the print nozzle to achieve the desired material composition at the desired location within the LDF. Once the LDF (e.g. monolith, film, or freeform) has been completely formed, the part is dried to remove residual organics and heat treated to form a transparent glass. The…

LLNL researchers have demonstrated a novel single-shot recording technology for transient optical signals in a time regime of picoseconds to nanoseconds for which currently there is a significant instrumentation gap.

The optical switching capability of optical semiconductors can be exploited in a pump-probe style architecture, where an auxiliary pump beam is crossed through the signal to sample a diagonal ‘slice’ of space-time, analogous to a rolling shutter. The slice is then imaged onto an ordinary camera, where the recorded spatial trace is a direct representation of the time content of the signal. The pump samples the signal by optically exciting carriers that modify the refractive index in a conventional semiconductor. The integrating response of the rapidly excited, but…

Lawrence Livermore researchers have developed a novel waveguide with resonant leakage elements that frustrate guidance at well-defined and selectable wavelengths. Based on this waveguide, the LLNL team has fabricated a Large Mode Area Neodymium doped fiber with suppression of the four-level transition around 1060 nm, and demonstrated lasing on the three-level transition at 930 nm with good efficiency.

LLNL's invention relates to optical waveguides in dielectric materials, specifically optical fibers (and amplifiers), which are typically longitudinally invariant. The critical waveguide properties are the modes they support, the coupling between these modes, and their propagation constants (or effective indices, neff). In particular, LLNL's invention provides means…

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Lawrence Livermore researchers are the first to successfully develop a practical fiber-optic amplifier that generates significant optical gain from 1,390 nanometers (nm) to 1,460 nm with relatively good efficiency. This discovery enables the potential for installed optical fibers to operate in an untapped spectral region known as the E-band, in addition to the C- and L-bands where they currently operate -- effectively doubling a single optical fiber's information-carrying potential.

LLNL’s new amplifier design is based on a novel Neodymium-doped microstructured optical fiber that is tailored to preferentially enhance optical signal gain in the E-band while effectively suppressing competing gain in other spectral bands. The new amplifier design is built around the same…

LLNL's invention uses energy efficient diode arrays for softening metals and alloys to enable friction stir process and friction stir welding. The use of intense light from compact, light-weight, and energy-efficient diode arrays to preheat the material being processed to the softening point eliminates defects associated with insufficient weld temperature such as tunnel voids.

The diode light heating enhancement (DLHE) of FSW also enables residual weld stress in the stir zone (SZ), the thermo-mechanically affected zone (TAZ) and the heat affected zone (HAZ) is controlled and minimized. The efficient and precisely controlled heating provided to FSW and FSP by DLHE can ultimately enable engineers to better control the microstructure that evolves in the weld.

The use of…

The selected industrial partner and LLNL will enter into a Cooperative Research and Development Agreement (CRADA) to develop the next generation of laser technologies for MEGa-ray systems and to create a next generation of MEGa-ray sources that could be marketed to both the industrial and academic communities.

The MEGa-ray system developed will be based on LLNL's proprietary, multi-GHz Compton scattering interaction geometry, calorimetric gamma-ray detectors, multi-GHz, photo-gun drive laser technology and kW-average-power, diode-pumped pulsed laser technology. The resulting integrated MEGa-ray source will be unique in the world and will target emerging business and science opportunities both in the U.S. and Europe. The successful execution of this CRADA will enable the U.S…

This technology comprises a method of depositing coatings of dissimilar materials on a substrate. A laser pulse hits the film of deposited material covered by a thin water layer. The laser deposition on the water-material interface generates huge pressure accelerating film to the velocities a few hundred meters per second. The film hits the substrate at an oblique angle. The high velocity of impact induces the plastic flow of materials on film-substrate interface and shear flow due to the oblique incidence results in material mixing and strong coating adhesion.

The five discrete steps involved in the deposition are as follows: (Step 1) the high-performance corrosion resistant film material is advanced with a spool assembly, and bathed with water that serves as a tamper during…

The SLIDER deflector includes a waveguide, a serrated mask positioned above the waveguide cladding, and a synchronized pump beam. The pump beam illuminates the serrated mask with a short pulse and transfers its pattern to the guiding layer where it imprints a sequence of prisms. The prisms are activated via nonlinear optical effects in the semiconductor and persist for the duration of the sweep. The signal beam is coupled into the waveguide and is deflected in piecewise segments by the fine sequence of prisms. Time-of-flight through the waveguide ensures a linear mapping of time to angle. Lenses at the output of the map the deflection onto the focal plane of a high fidelity camera where the signal can be recorded in parallel with high resolution and with high dynamic range.

LLNL's Slurry Stabilization Method provides a chemical means of stabilizing a polishing compound in suspension at working concentrations without reducing the rate of material removal. The treated product remains stable for many months in storage.

LLNL’s system consists of one or more flashlamp-pumped Nd:glass zig-zag amplifiers, a very low threshold stimulated-Brillouin-scattering (SBS) phase conjugator system, and a free-running single frequency Nd:YLF master oscillator.