Self-synchronized ultrafast electron beam diagnostics using a split-ring resonator driven by multicycle THz pulses

Abstract

The single-cycle THz-driven streaking technique, renowned for its high temporal resolution in ultrafast beam diagnostics, faces challenges in improving streaking field excitation efficiency. Recent interest has focused on using strong fields generated in subwavelength structures driven by multicycle THz pulses to enhance THz-based electron acceleration and manipulation. This paper presents a method that utilizes the interaction between an electron beam and a reflective hole array grating to generate a multicycle THz pulse for exciting a split-ring resonator (SRR). By integrating a subwavelength hole array into a conventional rectangular grating, we optimize Smith-Purcell (SP) radiation characteristics and significantly increase radiation intensity. Adjusting the hole array width allows precise control of the THz pulse frequency, aligning it with the SRR’s resonant frequency for efficient excitation. Theoretical analysis and simulations validate the method’s feasibility, showcasing exceptional streaking performance and femtosecond temporal resolution. This method advances narrowband THz source development based on the SP radiation and introduces a novel excitation strategy for THz streak cameras