The present disclosure may provide a field emission device with an enhanced beam convergence. For this, the device may include a gate structure disposed between a cathode electrode and an anode electrode, wherein the gate structure includes a gate electrode and an atomic layer sheet disposed on the gate electrode, the gate electrode facing an emitter and having at least one aperture formed therein.

A vacuum electronic device includes a multi-layer graphene grid that includes at least two layers of graphene, where the transmission of electrons through the multi-layer graphene grid can be tuned by varying the parameters of the vacuum electronic device such as the number of graphene layers, relative positions of the electrodes, voltage biases applied to the electrodes, and other device parameters.

Graphene grids are configured for applications in vacuum electronic devices. A multilayer graphene grid is configured as a filter for electrons in a specific energy range, in a field emission device or other vacuum electronic device. A graphene grid can be deformable responsive to an input to vary electric fields proximate to the grid. A mesh can be configured to support a graphene grid.

A device includes an anode, a cathode, and a grid configured to modulate a flow of electrons from the cathode to anode. The grid is made of graphene material which is substantially transparent to the flow of electrons.

A field emission device is configured with a grid that includes nanotubes or nanowires. In one embodiment a cathode, an anode, and a nanotube or nanowire grid are responsive to inputs to produce a potential barrier between the grid and at least one of the cathode and the anode such that a set of electrons from the cathode can tunnel through the potential barrier to produce a net current at the anode.

A Tera Hertz reflex klystron includes an electron emission unit, a resonant unit and an output unit. The electron emission is used to emit a plurality of electrons. The electron emission unit defines a first opening. The resonant unit comprises a resonant cavity frame. The resonant cavity frame comprises a top wall and a bottom wall and defines a resonant cavity. The top wall and the bottom wall faces with each other. The bottom wall comprises a bottom opening. The top wall comprises a top opening and at least one outputting hole. The bottom opening and the first opening are merged with each other. The output unit being configured to output Tera Hertz waves. The plurality of electrons are transferred to the output unit from the at least one outputting hole.

The present disclosure provides a charged particle beam device capable of simultaneously achieving protection of a charged particle source against electrical discharging inside a charged particle gun and highly accurate control of the charged particle gun, for both DC and AC components. A charged particle gun according to the present disclosure is configured such that an extraction voltage and an acceleration voltage are superposed and supplied to a charged particle beam source, a wiring between the charged particle beam source and a voltage circuit is covered with first and second enclosures, the first enclosure is configured to be connected to an extraction electrode, and the second enclosure is configured to be connected to an acceleration electrode and to a reference voltage of the voltage circuit.

An electron emitter structure includes an electron emission layer which is arranged to have a first side and a second side, and an electron accelerating structure which is arranged on the first side of the electron emission layer. The electron emission layer has a mixture of metals so as to be atmospherically stable. The electron accelerating structure has at least one electrode which is electrically insulated from the electron accelerating structure so as to form an acceleration path which allows electrons which are released from the electron emission layer to be selectively accelerated upon generation of an adjustable electric field. The acceleration path has a length l of from 10 nm to 1 m.

A pulsed generator of electrically charged particles includes a vacuum chamber; wherein the vacuum chamber is configured to maintain an internal operating pressure between 10-6 mbar and atmospheric pressure; the vacuum chamber is configured to accommodate a photocathode and an anode, the photocathode and the anode being separated by an adjustable distance less than or equal to 30 mm; the vacuum chamber includes a window enabling pulsed light to reach firstly a rear face of the photocathode; the anode is arranged downstream of the photocathode and has an orifice suitable for the passage of electrically charged particles; the generator of electrically charged particles includes a system to apply a difference in potential between the photocathode and the anode, the voltage being configured to accelerate the charged particles.

An electron source includes a plurality of electron emission cathodes and at least one control electrode. A gate current regulator is provided for regulation of current flowing through the at least one control electrode.