Double-line terawatt OPCPA laser system for exciting beat wave oscillations

A double-line terawatt beat laser (BEAT) is developed for exciting beat wave oscillations. BEAT consists of two oscillators and an amplification system including optical parametric chirped-pulse amplification (OPCPA) in which two individual pulses with wavelength separations of 10–35 nm are amplified, recompressed, and focused as a single beam. The recompressed pulse trace shows that a 150-fs pulse duration full width at half maximum was modulated at a beating period of 72 fs. This beating period matches a resonant excitation of plasma wave with an electron density of 2.5 × 10¹⁸ cm^?3, resulting in excitation of a beat wave in hydrogen plasma with wave amplitude of 15 GV/m. The multiple beating oscillations can amplify the plasma wave and improve its structure. This scheme would be ideal for stabilizing the plasma wave strength in the plasma cavity and for realizing a practical laser plasma accelerator.