Multi-pass cell spectral broadening at high pulse energies

Abstract

We simulate experimental conditions for nonlinear spectral broadening and compression of multi-joule, sub-picosecond, and femtosecond laser systems focusing on 1  μm center wavelength. The spatial, spectral, and temporal properties of two distinct cases are investigated in detail. The first system is a short multi-pass cell with 0.1–0.5 J pulse energy operated at higher helium pressures, used to illustrate the transition between Kerr-effect induced spectral broadening and spectral broadening in plasma. The second case is a long ten-joule multi-pass cell operated at few Pascal pressure range. These examples cover the operational extent of plasma spectral broadening in a multi-pass cell. Effects pertaining to plasma spectral broadening, including imperfect spatial beam profiles and initial non-zero nonlinear phase, are investigated, as well as scalability.