Powder atomic layer deposition process is used to coat nanopowders of host materials (e.g. yttrium aluminum garnet) with optically active neodymium organometal precursor followed by O2/O3 RF plasma to convert to a single layer of Nd2O3. The process can be repeated to build arbitrarily thick layers with custom doping profiles and followed by post-…
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![Diffuse discharge circuit breaker with latching switch](/sites/default/files/styles/scale_exact_400x400_/public/2024-02/Diffuse%20discharge%20circuit%20breaker.png?itok=qWpciEtY)
A thyristor will stay conducting until the current through the device is zero (“current zero”) or perhaps slightly negative. LLNL’s approach is to use the opticondistor (“OTV”) to force this current zero in order to force the device into an “off” state. By combining a light-activated thyristor with an OTV, a noise-immune, high efficiency, high-power switching device can be constructed. The…
![A cross-sectional schematic of a diffused Ga2O3 photoconductive semiconductor switch (PCSS)](/sites/default/files/styles/scale_exact_400x400_/public/2024-02/a%20cross-sectional%20schematic%20of%20a%20diffused%20beta-Ga2O3%20PCSS.png?itok=Z41s0FbO)
The researchers’ approach leverages the concept that dopants have high diffusivities in Ga2O3; the key lies in the selection of the appropriate dopant. This LLNL invention describes two device types that employ this design:
![Laser peening induces deep compressive stress, which significantly extends the service lifetime over any conventional treatment](/sites/default/files/styles/scale_exact_400x400_/public/2024-02/laser%20peening%20inducing%20deep%20compressive%20stress.png?itok=oMzDBpkP)
This invention proposes using a pulse laser configured to generate laser pulses and a controller for controlling operation of the pulse laser. The controller is further configured to control the pulse laser to cause the pulse laser to generate at least one of the laser pulses with a spatiotemporally varying laser fluence over a duration of at least one of the laser pulses. The spatiotemporally…
![Samples of optimized diamond switches](/sites/default/files/styles/scale_exact_400x400_/public/2024-01/Samples%20of%20optimized%20diamond%20switches.png?itok=5syzdD0q)
Design and construction of a photoconductive switch requires a diamond photoconductor illuminated by light of a certain excitation wavelength.
Characteristics of the LLNL-developed switch are as follows:
![Custom PCB design of a PCSS Laser Diode Driver](/sites/default/files/styles/scale_exact_400x400_/public/2023-11/PCSS%20Laser%20Diode%20Driver.png?itok=WQ2FNHQF)
LLNL researchers have invented an ultrafast PCSS to drive a high-power laser diode with arbitrary pulse widths. These devices operate by supplying a high voltage (>10 kV) to one side of the switch. A short pulse of light illuminates the semiconductor, instantly turning it from highly resistive to highly conductive.
![twister oven component with reflective inner cylinder surface](/sites/default/files/styles/scale_exact_400x400_/public/2023-06/twister%20oven%20component.png?itok=v3jlzm2V)
U.S. Patent No. 11,555,965 describes LLNL’s invention of “Illumination Frustums” for photoconductive switches to capture and “frustrate” the light from leaving the frustum. LLNL researcher’s latest novel invention, “Twister Oven”, achieves this by encouraging laser light absorption in a photo conductor material. Light enters the oven twisting and reflecting, making near normal incident multi…
![A photoconductive switch made from a synthetic, chemical vapor deposition diamond under test](/sites/default/files/styles/scale_exact_400x400_/public/2023-06/Photoconductive%20switch.jpg?itok=xC1O7vXg)
Design and construction of a photoconductive switch requires a diamond photoconductor illuminated by light of a certain excitation wavelength. The diamond material is chosen to be doped with substitutional nitrogen to act as a source of electrons. The device architecture allows maximum light entering the aperture. The top and bottom electrodes are made of ultra-wide bandgap (UWBG)…
![schematic of LLNL’s field emission photocathode device architecture with examples of tunable SiC surface micro- and nanostructures fabricated at LLNL](/sites/default/files/styles/scale_exact_400x400_/public/2023-05/FE%20photocathode%20device.png?itok=z-1Om9v8)
LLNL researchers faced this challenge by bridging the gap between VEDs and solid-state electronics (SSE). Their approach was to create a hybrid vacuum microelectronic device (VMD) architecture that combines the properties of vacuum as the electronic medium and the compact form factor and manufacturing scalability of semiconductor microelectronic chips.
![Segments of transmission line lengths can be switched to open circuit (as shown) or shorted to the ground (not shown)](/sites/default/files/styles/scale_exact_400x400_/public/2023-05/Segments%20of%20tranmission%20line%20lengths.png?itok=FF0qaBGw)
Design and construction of a photoconductive switch requires a diamond photoconductor illuminated by light of a certain excitation wavelength. The diamond material is specifically doped with substitutional nitrogen, which act as a source of electrons. The device architecture allows maximum light entering the aperture. The top and bottom electrodes are made of ultra wide band gap (UWBG)…
![Annular illumination on photo conductor by Conical Total Internal Reflection “CTIR” endcap](/sites/default/files/styles/scale_exact_400x400_/public/2023-05/CONIFR.png?itok=L4wSanXF)
The approach is to use a custom-designed frustrum and attach it to the optical fiber that connects to the PCSS. Light from the fiber enters the frustrum, spreads out, and enters the PCSS. Any unabsorbed light re-enters the frustrum and, because of its geometry, reflects back into the PCSS itself with only a negligible fraction escaping from the fiber. The shape of the novel frustrum is…
![AI Innovation Incubator](/sites/default/files/styles/scale_exact_400x400_/public/2022-01/AI%20Innovation%20Incubator.jpg?itok=B8jcKPOy)
Lawrence Livermore National Laboratory (LLNL) is offering the opportunity to collaborate in accelerating artificial intelligence (AI) for applied science, including research in key areas such as advanced material design, 3D printing, predictive biology, energy systems, “self-driving” lasers and fusion energy research.
![Catalyst HPC cluster](/sites/default/files/styles/scale_exact_400x400_/public/2022-06/Catalyst%20HPC%20cluster.jpg?itok=k9uYS5xL)
Clinical images have a wealth of data that are currently untapped by physicians and machine learning (ML) methods alike. Most ML methods require more data than is available to sufficiently train them. In order to obtain all data contained in a clinical image, it is imperative to be able to utilize multimodal, or various types of, data such as tags or identifications, especially where spatial…
![medical_x-rays_x-ray_tech](/sites/default/files/styles/scale_exact_400x400_/public/2022-06/medical_x-rays_x-ray_tech_1.jpg?itok=kn0J-DkH)
Some COVID-19 diagnoses are utilizing computed tomography (CT)-scans for triage. CT-scans produce immediate results with high sensitivity. The digital images produced by a CT-scan require physicians to identify objects within the image to determine the presence of disease. Object identification can be done using machine learning (ML) techniques such as deep learning (DL) to improve speed and…
![MimicGAN data set example](/sites/default/files/styles/scale_exact_400x400_/public/2020-05/mimicgan_robustness_to_rotation.png?itok=yacM18ra)
MimicGAN represents a new generation of methods that can “self-correct” for unseen corruptions in the data out in the field. This is particularly useful for systems that need to be deployed autonomously without needing constant intervention such as Automated Driver Assistance Systems. MimicGAN achieves this by treating every test sample as “corrupt” by default. The goal is to determine (a) the…
![creation of ultra-high energy density matter by an intense laser pulse](/sites/default/files/styles/scale_exact_400x400_/public/2022-06/laser_update875.jpg?itok=793sEzmU)
![AgAg2S reference electrode](/sites/default/files/styles/scale_exact_400x400_/public/2022-06/AgAg2S%20reference%20electrode.jpg?itok=kL2OzfHy)
LLNL has developed a reference electrode that is a great improvement on the widely used silver or platinum wire QRE commonly used in electrochemistry in ionic liquids. This new reference electrode, based on a silver-sulfide coated silver wire, exhibits greatly improved stability over a QRE. The stability of our RE approaches that of the Ag/Ag+ RE, but unlike the Ag/Ag+ RE, the RE reported here…
![medical_x-rays_x-ray_tech](/sites/default/files/styles/scale_exact_400x400_/public/2022-06/medical_x-rays_x-ray_tech_1.jpg?itok=kn0J-DkH)
LLNL has developed a new system, called the Segmentation Ensembles System, that provides a simple and general way to fuse high-level and low-level information and leads to a substantial increase in overall performance of digital image analysis. LLNL researchers have demonstrated the effectiveness of the approach on applications ranging from automatic threat detection for airport security, to…
![nuclear reactor](/sites/default/files/styles/scale_exact_400x400_/public/2022-06/nuclear%20reactor.jpg?itok=RMgGfrZv)
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.
![Laser Peening](/sites/default/files/styles/scale_exact_400x400_/public/2022-06/Laser%20peening.jpg?itok=l2OKtGme)
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.