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GaNC PCSS with integrated UV and IR emitters

This LLNL invention is a wide bandgap (WBG) or ultra-wide bandgap (UWBG) material comprising a PCSS that is modified, either chemically through alloying and/or mechanically through strain fields, in order to tune the energetic positions of the valence and/or conduction bands and the associated optical transition energies that create and quench the PCSS responsivity.

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CT Scanner Adobe Stock Image

The essence of this invention is a method that couples network architecture using neural implicit representations coupled with a novel parametric motion field to perform limited angle 4D-CT reconstruction of deforming scenes.

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Diffuse discharge circuit breaker with latching switch

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…

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A cross-sectional schematic of a diffused Ga2O3 photoconductive semiconductor switch (PCSS)

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:

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Samples of optimized diamond switches

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:

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Custom PCB design of a PCSS Laser Diode Driver

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. Ultrawide bandgap (UWBG) semiconductors are used to achieve sub-…

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schematic of LLNL’s field emission photocathode device architecture with examples of tunable SiC surface micro- and nanostructures fabricated at LLNL

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.

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SEM image of a prototype for a neural implant shuttle etched into a non-SOI wafer. The 7:1 (Si:Photoresist) etch selectivity used here allowed for a maximum structure height of 32 μm, with up to 75 steps of 0.4 μm height each. Scale bar 100 μm.

For this method, a Silicon on Insulator (SOI) wafer is used to tailor etch rates and thickness in initial steps of the process.  The simple three step process approach is comprised of grayscale lithography, deep reactive-ion etch (DRIE) and liftoff of the SOI wafer.  The liftoff process is used to dissolve the insulating layer, thus separating sections of the wafer as individual…

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Segments of transmission line lengths can be switched to open circuit (as shown) or shorted to the ground (not shown)

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…

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Annular illumination on photo conductor by Conical Total Internal Reflection “CTIR” endcap

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…

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Livermore Tomography Tools  LTT

To solve these challenges using new and existing CT system designs, LLNL has developed an innovative software package for CT data processing and reconstruction. Livermore Tomography Tools (LTT) is a modern integrated software package that includes all aspects of CT modeling, simulation, reconstruction, and analysis algorithms based on the latest research in the field. LTT contains the most…