title: Interplay of wavelength, fluence and spot-size in free-electron laser ablation of cornea.
abstract: Infrared free-electron lasers ablate tissue with high efficiency and low collateral damage when tuned to the 6-microm range. This wavelength-dependence has been hypothesized to arise from a multi-step process following differential absorption by tissue water and proteins. Here, we test this hypothesis at wavelengths for which cornea has matching overall absorption, but drastically different differential absorption. We measure etch depth, collateral damage and plume images and find that the hypothesis is not confirmed. We do find larger etch depths for larger spot sizes--an effect that can lead to an apparent wavelength dependence. Plume imaging at several wavelengths and spot sizes suggests that this effect is due to increased post-pulse ablation at larger spots.
authors.affiliation: Department of Physics & Astronomy, Vanderbilt University, Nashville, TN 37235, USA. shane.hutson@vanderbilt.edu
authors.forename: M Shane
authors.initials: MS
authors.lastname: Hutson
authors.forename: Borislav
authors.initials: B
authors.lastname: Ivanov
authors.forename: Aroshan
authors.initials: A
authors.lastname: Jayasinghe
authors.forename: Gilma
authors.initials: G
authors.lastname: Adunas
authors.forename: Yaowu
authors.initials: Y
authors.lastname: Xiao
authors.forename: Mingsheng
authors.initials: M
authors.lastname: Guo
authors.forename: John
authors.initials: J
authors.lastname: Kozub
mesh_terms: D000818:Animals; D003198:Computer Simulation; D003315:Cornea / Q000033:anatomy & histology / Q000502:physiology* / Q000601:surgery*; D048988:Corneal Surgery, Laser / Q000379:methods*; D004583:Electrons; D066298:In Vitro Techniques; D008027:Light; D008954:Models, Biological; D011829:Radiation Dosage; D012542:Scattering, Radiation; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013552:Swine