Nonlinear refractive index of porcine cornea studied by z-scan and self-focusing during femtosecond laser processing.
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.
Miclea
M
M
Martin-Luther-University Halle-Wittenberg, Physics Faculty, Optics Department, Von-Danckelmann-Platz 3, D-06120 Halle (Saale), Germany.
Skrzypczak
U
U
Faust
S
S
Fankhauser
F
F
Graener
H
H
Seifert
G
G
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