Monochromaticity of coherent Smith-Purcell radiation from finite size grating

Abstract

Investigation of coherent Smith-Purcell Radiation (SPR) spectral characteristics was performed both experimentally and by numerical simulation. The measurement of SPR spectral line shapes of different diffraction orders was carried out at KEK LUCX facility. A pair of room-temperature Schottky barrier diode (SBD) detectors with sensitivity bands of 60 − 90 GHz and 320 − 460 GHz was used in the measurements. Reasonable agreement of experimental results and simulations performed with CST Studio Suite justifies the use of different narrow-band SBD detectors to investigate different SPR diffraction orders. It was shown that monochromaticity of the SPR spectral lines increases with diffraction order. The comparison of coherent transition radiation and coherent SPR intensities in sub-THz frequency range showed that the brightnesses of both radiation mechanisms were comparable. A fine tuning feasibility of the SPR spectral lines is discussed.

Improved third-order nonlinear effect in graphene based on bound states in the continuum

“…3(a) and 3(b), we obtain that Δλ∕λ Γ are 0.0356% and 0.0175% for the cases with E f 0.23 eV and E f 0.7 eV, respectively, which is much less than the relative linewidth (about 1% in Ref. [65]). This means that the TH conversion efficiency is low when the frequency is taken at the deviation of the BICs.…”

Sub-THz radiation from dielectric capillaries with reflectors

“…The noncentral propagation of the beam in the corrugated capillary yielded 10-fold increase in the radiation intensity. Issues that remain to be considered in the future work are further investigations of how sensitive is the radiation directivity pattern to the transverse beam position; studies of the beam dynamics during and after propagation through the capillaries; and spectral measurements for a single and a multi-bunch beam, similar to the measurements described in [16].…”

Generation of a femtosecond electron microbunch train from a photocathode using twofold Michelson interferometer

“…Figure 4 shows a schematic diagram of the experimental setup. The LUCX is a multipurpose linear electron accelerator that was initially designed as an rf gun test bench and later extended for two projects: one to develop an x-ray source based on Compton scattering [25,26] and one to investigate coherent radiation [27][28][29][30][31]. The LUCX consists of a high mode separation 3.6 cell rf gun with a Cs 2 Te photocathode [32] and a normal conductivity 1 m 12-cell mode-separated linac booster [27].…”