Interaction mechanism of a terahertz wave generator using a field emission cathode

Abstract

Effect of aspect ratio and anode location on the field emission properties of a single tip based emitter J. Vac. Sci. Technol. B 23, 632 (2005); 10.1116/1.1880072Modeling of emitted current distribution and electron trajectories in the thin-film field-emission triodeThe interactions between the electrons and the terahertz waves in a vacuum electronic device based on field emission have been studied by employing the finite-difference time-domain particle-in-cell simulations. To understand the interaction mechanism, the cathode has been trimmed to emit electrons. The simulation results show that the efficiency of the case corresponding to the trimmed cathode is up to about 4% and higher than that of the original planar cathode. It is found that the interaction regions are located among the gaps between the cathode and the anode. In addition, the ac electric fields of the terahertz waves not only velocity modulate the electron beam but also cause the density modulation of the field emission current. The inertial bunching and prebunching effects provide the feedback loop as required by an oscillator.

Field Emission Lamps Prepared with Dip-Coated and Nickel Electroless Plated Carbon Nanotube Cathodes

“…amplifiers. [15][16][17] Field emission lamps (FELs) as a new light source possess higher luminous efficiency than incandescent lights. 18 19 More importantly, in contrast to another type of major light sources-fluorescent lamps, FELs are mercury-free.…”

Broadband Terahertz Source Based on Photomixing in Laser-Assisted Field Emission with Clusters of Carbon Nanotubes

“…The current density for emitters that are made of refractory metals such as tungsten may be as high as 10 9 A/m 2 in steady state, or 10 12 A/m 2 when the applied electric field is pulsed (Gomer, 1993). Some have used field emitters in place of heated filaments as the electron source in microwave triodes (Schwoebel et al, 2005), klystrons (Ryskin et al, 2007), traveling-wave tubes (Makishima et al, 1999;Lin & Lu, 2007), and the closely-related monotron (Yokoo & Ishihara, 1997). Others have used femtosecond lasers to obtain pulses of electrons that are shorter than 70 fs in laser-assisted field emission (Hommelhoff et al, 2006) and analysis shows that there is a fundamental limit at 2 fs (Hagmann, 1998A).…”