Konstantin G. Batrakov

First lasing of a volume FEL (VFEL) at a wavelength range λ∼4–6 mm

First lasing of a volume free electron laser in the millimeter wavelength range is observed.

Progress of the volume FEL (VFEL) experiments in millimeter range

Use of non-one-dimensional distributed feedback in Volume Free Electron Laser gives possibility of frequency tuning in wide range. In present work, dependence of lasing process on the angle between resonant diffraction grating grooves and direction of electron beam velocity is discussed.

Application of volume diffraction grating for TeraHertz lasing in volume FEL (VFEL)

The generation of induced radiation in volume resonator formed by metal threads is considered. It is shown that using of such volume diffraction grating allows increasing of lasing efficiency in the terahertz range. The requirements with regard to beam and grating parameters are obtained.

Use of dynamical undulator mechanism to produce short wavelength radiation in volume FEL (VFEL)

VFEL lasing in a system with a dynamical undulator is described. In this system radiation of long wavelength creates the undulator for lasing at a shorter wavelength. Two diffraction gratings with different spatial periods form the VFEL resonator. The grating with longer period pumps the resonator with the long wavelength radiation to provide the necessary amplitude of the undulator field. The grating with the shorter period is used to select the mode for the short wavelength radiation. Lasing of such a system in the terahertz frequency range is discussed.

Dependence of volume FEL (VFEL) threshold conditions on undulator parameters

The volume free electron laser uses a volume distributed feedback (VDFB), which can essentially reduce the threshold current of generation providing the possibility of a smooth frequency tuning. An undulator VFEL is considered.

Wide range frequency tuning in vacuum electronic devices

New possibilities of frequency tuning in vacuum electronic devices are considered by the example of volume free electron laser. Recent experimental results are presented along with some theoretical comments and technical proposals. Experimental study of dependence of radiation frequency and intensity on change of the angular orientation of grooves of diffraction gratings with respect to electron beam velocity due rotation of diffraction gratings is presented. Two geometries of diffraction are analyzed: those of Bragg and Laue. Change of lasing efficiency with grating rotation is considered. VFEL generator is proposed as a new type of tunable backward wave tube with variable period (due to gratings rotation) and VFEL amplifier is considered as a new type of tunable traveling wave tube.