A vacuum electron tube comprises at least one electron-emitting cathode and at least one anode arranged in a vacuum chamber, the cathode having a planar structure comprising a substrate comprising a conductive material, a plurality of nanotube or nanowire elements electrically insulated from the substrate, the longitudinal axis of the nanotube or nanowire elements substantially parallel to the plane of the substrate, and at least one first connector electrically linked to at least one nanotube or nanowire element so as to be able to apply a first electrical potential to the nanowire or nanotube element.

A dielectric coated plasmonic photoemitter is provided. An aspect of the present photonic apparatus includes a conductive photoemitter including a dielectric material coating or layered on a metallic core. The dielectric material being configured to enhance a local optical field strength and current density of the photoemitter as compared to a bare photoemitter without the dielectric layer. The dielectric layered photoemitter being tunable to transmit photoemissions from corners thereof with different photonic characteristics depending on a laser wavelength pulse received.

A dielectric coated plasmonic photoemitter is provided. An aspect of the present photonic apparatus includes a conductive photoemitter including a dielectric material coating or layered on a metallic core. The dielectric material being configured to enhance a local optical field strength and current density of the photoemitter as compared to a bare photoemitter without the dielectric layer. The dielectric layered photoemitter being tunable to transmit photoemissions from corners thereof with different photonic characteristics depending on a laser wavelength pulse received.

Provided is a low-cost magnetron that is excellent in productivity without any adverse effect on characteristics. Two large and small strap rings 11 (11A and 11B) are only disposed at lower ends, or input sides, of a plurality of vanes 10 (10A and 10B) in the direction of a tube axis m. Diameter Rip of a protruding flat surface 41 of an input side pole piece 18 is larger than diameter Rop of a protruding flat surface 40 of an output side pole piece 17. Therefore, it is possible to provide a practical magnetron without a significant decrease in productivity or characteristics from a conventional one, while cutting costs by reducing the number of parts with the use of two strap rings on one side.

Provided is a low-cost magnetron that is excellent in productivity without any adverse effect on characteristics. Two large and small strap rings 11 (11A and 11B) are only disposed at lower ends, or input sides, of a plurality of vanes 10 (10A and 10B) in the direction of a tube axis m. Diameter Rip of a protruding flat surface 41 of an input side pole piece 18 is larger than diameter Rop of a protruding flat surface 40 of an output side pole piece 17. Therefore, it is possible to provide a practical magnetron without a significant decrease in productivity or characteristics from a conventional one, while cutting costs by reducing the number of parts with the use of two strap rings on one side.

The disclosure relates to a detecting system including a terahertz wave source, a detector and a controlling computer. The terahertz wave source includes a terahertz reflection klystron including an electron emission unit, a resonance unit, an output unit. The electron emission unit is configured to emit electrons. The resonance unit includes a resonant cavity communicated with the electron emission unit so that the electron emission unit emit electrons into the resonant cavity. The resonant cavity of the electron emission unit opposite the cavity wall has an output aperture coupled. The output unit is communicated with the resonance unit by the output aperture coupled. The resonance unit generate terahertz wave transmit to the output unit by the output aperture coupled.

The disclosure relates to a detecting system including a terahertz wave source, a detector and a controlling computer. The terahertz wave source includes a terahertz reflection klystron including an electron emission unit, a resonance unit, an output unit. The electron emission unit is configured to emit electrons. The resonance unit includes a resonant cavity communicated with the electron emission unit so that the electron emission unit emit electrons into the resonant cavity. The resonant cavity of the electron emission unit opposite the cavity wall has an output aperture coupled. The output unit is communicated with the resonance unit by the output aperture coupled. The resonance unit generate terahertz wave transmit to the output unit by the output aperture coupled.

A coaxial amplifier having at least one electron beam is provided. The amplifier may include a conductive rod, a plurality of parallel discs on the rod, a cathode array for producing at least one electron beam. When a plurality of electron beams are formed they are arranged in an annular configuration around said rod and disks, and directed along said rod and coaxially thereof. A first waveguide may apply electromagnetic wave energy to one end of said disc and rod assembly to induce propagation of said energy along said assembly. A second waveguide may extract the amplified electromagnetic energy from the other end of the disc and rod assembly.

A coaxial amplifier having at least one electron beam is provided. The amplifier may include a conductive rod, a plurality of parallel discs on the rod, a cathode array for producing at least one electron beam. When a plurality of electron beams are formed they are arranged in an annular configuration around said rod and disks, and directed along said rod and coaxially thereof. A first waveguide may apply electromagnetic wave energy to one end of said disc and rod assembly to induce propagation of said energy along said assembly. A second waveguide may extract the amplified electromagnetic energy from the other end of the disc and rod assembly.

An electron gun includes: a cathode, which has a cathode holder and a cathode body; and a Wehnelt cylinder. The cathode holder receives the cathode body and the Wehnelt cylinder is suitable for bundling free electrons, which can escape from the cathode body toward the Wehnelt cylinder, to form an electron beam. The Wehnelt cylinder is interlockingly arranged, at least in some parts along a first inner surface facing the cathode holder, on an outer surface of the cathode holder and at least partly extends around the cathode holder.