title: Sub-critical regime of femtosecond inscription.
abstract: We apply well known nonlinear diffraction theory governing focusing of a powerful light beam of arbitrary shape in medium with Kerr nonlinearity to the analysis of femtosecond (fs) laser processing of dielectric in sub-critical (input power less than the critical power of self-focusing) regime. Simple analytical expressions are derived for the input beam power and spatial focusing parameter (numerical aperture) that are required for achieving an inscription threshold. Application of non-Gaussian laser beams for better controlled fs inscription at higher powers is also discussed.
authors: Sergei K
authors: SK
authors: Turitsyn
authors: Vladimir K
authors: VK
authors: Mezentsev
authors: Mykhaylo
authors: M
authors: Dubov
authors: Alexander M
authors: AM
authors: Rubenchik
authors: Michail P
authors: MP
authors: Fedoruk
authors: Evgeny V
authors: EV
authors: Podivilov