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.

In order to suppress the amount of time needed for the start-up of a microwave tube carried out when voltage fed from a power source has decreased, while avoiding increase in scale of a power storage unit, this power supply device includes: a power supply unit that supplies power fed from the power source to the microwave tube that is provided with a cathode, a heater for heating the cathode, an anode, and a collector; a power storage unit that stores the fed power and, if the voltage of the fed power decreases, supplies stored power that is power obtained by the power storing, to the microwave tube; and a power supply switching unit that, if the voltage of the fed power decreases, stops supplying the stored power to the anode and does not stop supplying the stored power to the heater.

In order to suppress the amount of time needed for the start-up of a microwave tube carried out when voltage fed from a power source has decreased, while avoiding increase in scale of a power storage unit, this power supply device includes: a power supply unit that supplies power fed from the power source to the microwave tube that is provided with a cathode, a heater for heating the cathode, an anode, and a collector; a power storage unit that stores the fed power and, if the voltage of the fed power decreases, supplies stored power that is power obtained by the power storing, to the microwave tube; and a power supply switching unit that, if the voltage of the fed power decreases, stops supplying the stored power to the anode and does not stop supplying the stored power to the heater.

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.

Traveling-wave tube amplifiers for high-frequency signals, including terahertz signals, and methods for making a slow-wave structure for the traveling-wave tube amplifiers are provided. The slow-wave structures include helical conductors that are self-assembled via the release and relaxation of strained films from a sacrificial growth substrate.

Vacuum electron devices (VEDs) are produced having a plurality of two-dimensional layers of various materials that are bonded together to form one or more VEDs simultaneously. The two-dimensional material layers are machined to include features needed for device operation so that when assembled and bonded into a three-dimensional structure, three-dimensional features are formed. The two-dimensional layers are bonded together using brazing, diffusion bonding, assisted diffusion bonding, solid state bonding, cold welding, ultrasonic welding, and the like. The manufacturing process enables incorporation of metallic, magnetic, and ceramic materials required for VED fabrication while maintaining required positional accuracy and multiple devices per batch capability. The VEDs so produced include a combination of magnetic and electrostatic lenses for electron beam control.

A high-power vacuum electron device source of 10 mm-0.1 mm wavelength radiation is composed of an electron gun joined to a RF vacuum electronic circuit. The electron gun includes a cathode, a focus electrode, and a grid. It generates an electron beam that is injected into the circuit for amplifying RF waves. The circuit is composed of metal circuit plates, e.g., copper alloy, that mate with each other and are shaped to provide a beam tunnel and RF circuit envelopes. Precision alignment pins made of nickel super alloy, are used to mutually align the metal circuit plates using elastic averaging implemented by positioning the precision alignment pins in precision alignment holes in the metal circuit plates. Preferably, the electron gun is aligned with the circuit using quasi-kinematic coupling.

A high-power vacuum electron device source of 10 mm-0.1 mm wavelength radiation is composed of an electron gun joined to a RF vacuum electronic circuit. The electron gun includes a cathode, a focus electrode, and a grid. It generates an electron beam that is injected into the circuit for amplifying RF waves. The circuit is composed of metal circuit plates, e.g., copper alloy, that mate with each other and are shaped to provide a beam tunnel and RF circuit envelopes. Precision alignment pins made of nickel super alloy, are used to mutually align the metal circuit plates using elastic averaging implemented by positioning the precision alignment pins in precision alignment holes in the metal circuit plates. Preferably, the electron gun is aligned with the circuit using quasi-kinematic coupling.