Triad National Security, LLC

The United States of America As Represented by the Department of Energy

Jeffrey Pietryga

Nathan Andrew Moody

John W Lewellen

Gautam Gupta

Aditya Mohite

Vitaly Pavlenko

Robert K Sander

Richard D Schaller

Hisato Yamaguchi

Michael Whitehead

Istvan Robel

Kirill K Zhuravlev

According to an embodiment of the present disclosure, a photocathode may include: a mesh having a first surface and a second surface facing away from the first surface, and including metallic, semiconductor or ceramic mesh grid with micron-sized openings in the mesh; a photosensitive film on the first surface of the mesh and extending at least partially into the openings of the mesh; and a graphene layer including one or more graphene sheets on the second surface of the mesh.

Photocathodes with protective in-situ graphene gas barrier films and method of making the same

A tunable photocathode for use in vacuum electronic devices includes a nanostructured photoemission layer including quantum confined nanostructures, such as quantum dots. The quantum confined nanostructures can be tuned (e.g., prepared to have various characteristics or parameters) in order to independently optimize various characteristics of the electron beam emitted by the photocathode. For example, by changing the material composition, size and geometry of the quantum confined nanostructures, the energy levels of the quantum confined nanostructures in the photoemission layer can be tuned to provide a photocathode having a high quantum efficiency, low emittance, fast response time to incident light pulses, long operational lifetime, and increased environmental stability compared with conventional photocathodes and cathodes in vacuum electronic devices.

Tunable quantum confinement and quantum dot photocathode

A fiber-based optical pressure-sensor, made using semiconductor nanocrystal quantum dots (NQDs) as the active transducing material, provides response time fast enough for shock wave measurements. For NQDs, the shift in band gap as a result of applied pressure can be observed as a shift of the photoluminescence (PL) peak. Further, the shift of the principal absorbance feature allows pressure measurements faster than those obtainable by following the PL peak.

Real time measurement of shock pressure

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Los Alamos, NM, United States of America

Jeffrey Pietryga