title: Nonlinear refractive index of porcine cornea studied by z-scan and self-focusing during femtosecond laser processing.
abstract: We have investigated the nonlinear refractive index of ex-vivo pig cornea by a combined approach using the standard z-scan technique on extracted corneas or corneal slices, as well as studying the deviations caused by self-focusing during femtosecond laser processing of the pig eyes. The experiments yield consistently an upper limit of 1.2 MW for the critical power of self-focusing in porcine cornea, and a value of 2 x 10(-19) m(2)/W for its nonlinear refractive index. We also demonstrate that due to this nonlinear refraction the cutting depth of typical fs-laser surgery processing in cornea may depend considerably, albeit in a well controllable way, on the laser parameters.
authors.affiliation: Martin-Luther-University Halle-Wittenberg, Physics Faculty, Optics Department, Von-Danckelmann-Platz 3, D-06120 Halle (Saale), Germany.
authors.forename: M
authors.initials: M
authors.lastname: Miclea
authors.forename: U
authors.initials: U
authors.lastname: Skrzypczak
authors.forename: S
authors.initials: S
authors.lastname: Faust
authors.forename: F
authors.initials: F
authors.lastname: Fankhauser
authors.forename: H
authors.initials: H
authors.lastname: Graener
authors.forename: G
authors.initials: G
authors.lastname: Seifert
mesh_terms: D000818:Animals; D003198:Computer Simulation; D003315:Cornea / Q000502:physiology* / Q000601:surgery*; D053685:Laser Therapy / Q000379:methods*; D008954:Models, Biological; D017711:Nonlinear Dynamics; D012031:Refractometry / Q000379:methods*; D013552:Swine