Improved ultraviolet field-emission lamps can be safely deployed close to people because they eliminate the use of toxic materials, mitigate heating issues, and emit light in a wavelength range that is safe for human exposure.

Improved ultraviolet field-emission lamps can be safely deployed close to people because they eliminate the use of toxic materials, mitigate heating issues, and emit light in a wavelength range that is safe for human exposure.

Improved ultraviolet field-emission lamps can be safely deployed close to people because they eliminate the use of toxic materials, mitigate heating issues, and emit light in a wavelength range that is safe for human exposure.

Improved ultraviolet field-emission lamps can be safely deployed close to people because they eliminate the use of toxic materials, mitigate heating issues, and emit light in a wavelength range that is safe for human exposure.

Improved ultraviolet field-emission lamps can be safely deployed close to people because they eliminate the use of toxic materials, mitigate heating issues, and emit light in a wavelength range that is safe for human exposure.

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.

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.

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.

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.

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.