Optically gated field emission cathodes

VALUE PROPOSITION

Electron beam-based devices are critical to applications such as particle accelerators, high-power electromagnetic sources ranging from microwave to X-rays, vacuum electronic devices, e-beam lithography, electron microscopy, space-vehicle neutralization and emerging vacuum nanodevices. They are key elements in telecommunication systems, satellite-based transmitters, radar, communication data links, and electronic countermeasures. There continues to be strong interest in increasing the output power, frequency tunability, and bandwidth of electron beam-based vacuum electronics devices, for uses as radiation sources and power amplifiers, from GHz to THz and beyond.

DESCRIPTION OF TECHNOLOGY

The present technology is direct density modulation of high current electron beam emission from an RF cold cathode using optical excitation. Pulsed photon sources combined with an RF field produce sharp, high-current electron bunches with pulse duration comparable with or even less than that of the optical pulse. An RF source is connected to an electron emitter or cold cathode, and a photon emitter such as a laser allows for frequency manipulation, fast timing control and/or amplification control. In this mode timing of the electron beam is not limited by the capacitance of the cathode circuit. The shape of the current pulse can be controlled by the system offering great flexibility in output. The combined RF and optical excitation create an emission current that is greater than using RF alone or optical excitation alone.

BENEFITS

Improved timing of electron beam emissions
Increased electron emission currents
Reduced RF bias
Breakdown can be mitigated to provide a more stable and robust emitter operation.

APPLICATIONS