Ultra-supercontinuum broadening from anti-Stokes to Stokes arising from fifth- and third-order susceptibilities from self-phase modulation for isotropic liquid, solid, and gaseous media with extremely intense visible femtosecond pump pulses

Ultra-supercontinuum (USC) broadening has been theoretically stimulated from the Kerr effect self-phase modulation of the fifth- and third-order susceptibilities under the influence of the envelope of an extremely high-intensity femtosecond laser pulse in condensed and gaseous media. The outcome can produce spectral changes extending from anti-Stokes side to UV and X-ray, and Stokes side to IR down to RF/DC. The theoretical results show that a high-intensity pulse as high as on the order of ~10¹⁶ W/m² can reveal the influence of the fourth-order refractive index n₄ arising from fifth-order susceptibility large enough that the nonlinear n₄I₀² term overtakes the n₂I₀ term to produce the ultra-supercontinuum broadening in the liquids such as CS₂ and N₂. Different femtosecond laser systems with J and mJ pulse energies have been used to study the USC generation in CS₂ and N₂ experimentally.