A HELAC device includes a semiconductor layer that absorbs incident photons, a graphene monolayer disposed over the semiconductor layer, and an insulator layer interposed between the semiconductor layer and graphene monolayer. The graphene monolayer is configured as a gate for the HELAC device while the insulator layer is configured to allow a voltage drop between the semiconductor layer and graphene. Advantageously, the HELAC device is configured to receive photons on an emitter surface and to emit hot electrons therefrom.

A photocathode emitter can include a transparent substrate, a photocathode layer, and a plasmonic structure array disposed between the transparent substrate and the photocathode layer. The plasmonic structure can serve as a spot-confining structure and an electrical underlayer for biasing the photocathode. The plasmonic structure can confine the incident light at subwavelength sizes.

Provided are an electron gun, an electron gun component, an electron beam applicator, and an alignment method that can align the emission axis of an electron beam with the optical axis of the electron optical system of the counterpart device even when misalignment of a mounted position of the electron gun being mounted to the counterpart device is larger. The electron gun includes: a light source; a vacuum chamber; a photocathode that emits an electron beam in response to receiving light from the light source; an electrode kit; and an electrode kit drive device, the electrode kit includes a photocathode supporting part, and an anode arranged spaced apart from the photocathode supporting part, the photocathode is placed on the photocathode supporting part, and the electrode kit drive device moves the electrode kit in an X-Y plane, where one direction is defined as an X direction, a direction orthogonal to the X direction is defined as a Y direction, and a plane including the X direction and the Y direction is defined as the X-Y plane.

A photocathode emitter includes a transparent substrate, a photocathode layer, and a plasmonic structure array disposed between the transparent substrate and the photocathode layer. The plasmonic structure array is configured to operate at a wavelength from 193 nm to 430 nm. The plasmonic structure array can be made of aluminum. An electron beam can be generated from a light beam directed at the plasmonic structure array of the photocathode emitter.

According to one embodiment, an electron-emitting element includes a first member and a second member. The first member includes a semiconductor member of an n-type. The second member includes a diamond member a p-type and includes at least one selected from the group consisting of diamond and graphite. The semiconductor member includes at least one selected from the group consisting of a first material, a second material, and a third material. The first material includes nitrogen and at least one selected from the group consisting of B, Al, In, and Ga. The second material includes at least one selected from the group consisting of ZnO and ZnMgO. The third material includes at least one selected from the group consisting of BaTiO.sub.3, PbTiO.sub.3, Pb(Zr.sub.x, Ti.sub.1-x)O.sub.3, KNbO.sub.3, LiNbO.sub.3, LiTaO.sub.3, Na.sub.xWO.sub.3, Zn.sub.2O.sub.3, Ba.sub.2NaNb.sub.5O.sub.5, Pb.sub.2KNb.sub.5O.sub.15, and Li.sub.2B.sub.4O.sub.7.

An electron beam source includes a photocathode or an anode attached to an ultraviolet semiconductor light source (SULS), or an anode incorporated between a SULS and a photocathode, and an electron beam gun using the electron beam source and electron beam pumped target. In certain embodiments the target is an electron beam pumped light emitting device. The photocathode surface is essentially parallel to the surface of the SULS which is a Light Emitting Diode, Superluminescent Diode, or Laser Diode. Different embodiments of the present disclosure include a photocathode directly attached to the SULS surface or having an intermediate transition layer or layers between the photocathode and the emitter. The transition layer includes a substrate on which the SULS is fabricated and/or a layer to facilitate light extraction from the SULS to the photocathode. The active region of the electron beam pumped light emitter is placed in the path of photoelectron flow to excite non-equilibrium electron-hole pairs and generate light emission at a wavelength or wavelengths determined by the energy band structure of the active region.

A night vision system along with an image intensifier tube and method for forming the tube are provided. The night vision system incorporates the image intensifier tube in both an analog channel as well as a digital channel, with an addressable display within the analog image intensifier tube analog channel configured to create an electronically addressable output. An analog image intensifier tube is included in the digital imager for presenting binary digital signals representative of an image, or of symbol indicia, and registering those digital representation from the digital imager onto one or more electron multipliers of the analog image intensifier tube within the analog channel. The provided night vision system also utilizes a cathodoluminescent screen, which is a highly efficient light source that reduces system power.

In a photoexcited electron source, a condenser lens optimally designed on an assumption that excitation light passes through a transparent substrate having a predetermined thickness and a predetermined refractive index cannot focus a focal point of the excitation light well on a photocathode film when the transparent substrate is different. Therefore, an optical spherical aberration correction plate 21 having a refractive index equal to a refractive index of a substrate of a photocathode at a wavelength of the excitation light is disposed between the photocathode 1 and the condenser lens 2. Alternatively, an optical spherical aberration corrector 20 configured to diverge or focus parallel light emitted to the condenser lens is provided. Accordingly, flares of the electron beam can be reduced and brightness of the photoexcited electron source can be increased.

The invention discloses a photocathode comprising an amorphous substrate such as a glass substrate (110) presenting an input face that will receive incident photons and a back face opposite the front face. Nanowires (120) made from at least one III-V semiconducting material are deposited on the back face of the substrate and extend from this face in a direction away from the front face. The invention also relates to a method for manufacturing such a photocathode by MBE.

Systems and methods for obtaining fast, spin-polarized electrons from an edge or tip or cusp of a target material, e.g., a sharp GaAs crystal edge or tip, or a cusp, which naturally incorporates optical reversibility. A source of fast spin-polarized electrons may include a target material including a sharp tip or tip portion or a sharp edge or a cusp, the tip or tip portion including at least two intersecting edges, and a pulsed light source configured to emit one or more light pulses focused on the sharp tip or tip portion or the sharp edge or the cusp to thereby induce emission of spin-polarized electrons from the sharp tip or tip portion or the sharp edge or the cusp of the target material.