Sub-critical regime of femtosecond inscription.
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.
Turitsyn
Sergei K
SK
Mezentsev
Vladimir K
VK
Dubov
Mykhaylo
M
Rubenchik
Alexander M
AM
Fedoruk
Michail P
MP
Podivilov
Evgeny V
EV