Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A high-brightness electron beam source is disclosed. The electron beam source may include a broadband illumination source configured to generate broadband illumination. A tunable spectral filter may be configured to filter the broadband illumination to provide filtered illumination having an excitation spectrum. The electron beam source may further include a photocathode configured to emit one or more electron beams in response to the filtered illumination, wherein emission from the photocathode is adjustable based on the excitation spectrum of the filtered illumination from the tunable spectral filter.

Abstract: A photocathode can include a body fabricated of a wide bandgap semiconductor material, a metal layer, and an alkali halide photocathode emitter. The body may have a thickness of less than 100 nm and the alkali halide photocathode may have a thickness less than 10 nm. The photocathode can be illuminated with a dual wavelength scheme.

Abstract: The system includes a photocathode electron source, diffractive optical element, and a microlens array to focus the beamlets. A source directs a radiation beam to the diffractive optical element, which produces a beamlet array to be used in combination with a photocathode surface to generate an array of electron beams from the beamlets.

Abstract: 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.

Abstract: A flat top laser beam is used to generate an electron beam with a photocathode that can include an alkali halide. The flat top profile can be generated using an optical array. The laser beam can be split into multiple laser beams or beamlets, each of which can have the flat top profile. A phosphor screen can be imaged to determine space charge effects or electron energy of the electron beam.

Abstract: The system includes a photocathode electron source, diffractive optical element, and a microlens array to focus the beamlets. A source directs a radiation beam to the diffractive optical element, which produces a beamlet array to be used in combination with a photocathode surface to generate an array of electron beams from the beamlets.

Abstract: An emitter with a diameter of 100 nm or less is used with a protective cap layer and a diffusion barrier between the emitter and the protective cap layer. The protective cap layer is disposed on the exterior surface of the emitter. The protective cap layer includes molybdenum or iridium. The emitter can generate an electron beam. The emitter can be pulsed.

Abstract: A photocathode structure, which can include one or more of Cs2Te, CsKTe, CsI, CsBr, GaAs, GaN, InSb, CsKSb, or a metal, has a protective film on an exterior surface. The protective film includes one or more of ruthenium, nickel, platinum, chromium, copper, gold, silver, aluminum, or an alloy thereof. The protective film can have a thickness from 1 nm to 10 nm. The photocathode structure can be used in an electron beam tool like a scanning electron microscope.

Abstract: A photocathode can include a body fabricated of a wide bandgap semiconductor material, a metal layer, and an alkali halide photocathode emitter. The body may have a thickness of less than 100 nm and the alkali halide photocathode may have a thickness less than 10 nm. The photocathode can be illuminated with a dual wavelength scheme.

Abstract: Electron source designs are disclosed. The emitter structure, which may be silicon, has a layer on it. The layer may be graphene or a photoemissive material, such as an alkali halide. An additional layer between the emitter structure and the layer or a protective layer on the layer can be included. Methods of operation and methods of manufacturing also are disclosed.

Abstract: A photocathode structure, which can include one or more of Cs2Te, CsKTe, CsI, CsBr, GaAs, GaN, InSb, CsKSb, or a metal, has a protective film on an exterior surface. The protective film includes one or more of ruthenium, nickel, platinum, chromium, copper, gold, silver, aluminum, or an alloy thereof. The protective film can have a thickness from 1 nm to 10 nm. The photocathode structure can be used in an electron beam tool like a scanning electron microscope.

Abstract: A photocathode can include a body fabricated of a wide bandgap semiconductor material, a metal layer, and an alkali halide photocathode emitter. The body may have a thickness of less than 100 nm and the alkali halide photocathode may have a thickness less than 10 nm. The photocathode can be illuminated with a dual wavelength scheme.

Abstract: An emitter with a diameter of 100 nm or less is used with a protective cap layer and a diffusion barrier between the emitter and the protective cap layer. The protective cap layer is disposed on the exterior surface of the emitter. The protective cap layer includes molybdenum or iridium. The emitter can generate an electron beam. The emitter can be pulsed.

Abstract: A high-brightness electron beam source is disclosed. The electron beam source may include a broadband illumination source configured to generate broadband illumination. A tunable spectral filter may be configured to filter the broadband illumination to provide filtered illumination having an excitation spectrum. The electron beam source may further include a photocathode configured to emit one or more electron beams in response to the filtered illumination, wherein emission from the photocathode is adjustable based on the excitation spectrum of the filtered illumination from the tunable spectral filter.

Abstract: A photocathode structure, which can include an alkali halide, has a protective film on an exterior surface of the photocathode structure. The protective film includes ruthenium. This protective film can be, for example, ruthenium or an alloy of ruthenium and platinum. The protective film can have a thickness from 1 nm to 20 nm. The photocathode structure can be used in an electron beam tool like a scanning electron microscope.

Abstract: Electron source designs are disclosed. The emitter structure, which may be silicon, has a layer on it. The layer may be graphene or a photoemissive material, such as an alkali halide. An additional layer between the emitter structure and the layer or a protective layer on the layer can be included. Methods of operation and methods of manufacturing also are disclosed.

Abstract: A photocathode structure, which can include an alkali halide, has a protective film on an exterior surface of the photocathode structure. The protective film includes ruthenium. This protective film can be, for example, ruthenium or an alloy of ruthenium and platinum. The protective film can have a thickness from 1 nm to 20 nm. The photocathode structure can be used in an electron beam tool like a scanning electron microscope.