Electron Energy Modulation with Optical Evanescent Waves

An electron beam is commonly used for generating and amplifying coherent electromagnetic waves over the wide-frequency spectrum of microwaves through to ultraviolet rays. Many kinds of electron beam devices, including the klystron, traveling wave tube (TWT), and backward wave oscillator (BWO), have been developed [1]. These beam devices have several advantages over semiconductor devices, such as a wide frequency tuning range and higher output power. These beam devices are mostly microwave or millimeter wave amplifiers or oscillators. Only free electron lasers (FEL) can oscillate in the visible region [2]. However, FELs use an electron accelerator as a beam source, so their applications are strongly limited. For general use, a new compact beam device similar to the semiconductor laser, is required.