Radiation effects on poly(methyl methacrylate) induced by pulsed laser irradiations |
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| Authors: | L. Torrisi A. Italiano E. Amato F. Caridi M. Cutroneo C. A. Squeri |
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| Affiliation: | 1. Dipartimento di Fisica dell'Universitá , Messina , Italy;2. Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud , Catania , Italy lorenzo.torrisi@unime.it;4. Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Messina , Messina , Italy;5. Dipartimento di Scienze Radiologiche dell'Universitá , Messina , Italy;6. Facoltá di Scienze MM.FF.NN. , Universitá di Messina , Messina , Italy;7. Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Messina , Messina , Italy;8. U.O.C. di Oftalmologia , Azienda Ospedaliera Universitaria , Messina , Italy |
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| Abstract: | Poly(methyl methacrylate) (PMMA) was irradiated using a medical UV-ArF excimer laser operating at the fundamental wavelength of 193 nm. Characterized by a beam diameter of 1.8 mm and energy of 180 mJ with a Gaussian energy profile, it operates in a single mode or at 30 Hz repetition rate. Mechanical profilometry was carried out on ablation craters in order to study the rugosity and the ablation yield in the various operative conditions. Optical transmission and reflection measurements at six wavelengths were conducted in order to characterize the optical properties of the irradiated surfaces. Measured crater depths in PMMA were lower with respect to the forecasted ones in corneal tissue, while the lateral crater aperture was maintained. The rugosity produced at the crater bottom after irradiation was about 0.3 μm, and the ablation yield was about 1015 molecules/laser pulse, while etching depth and diameter show a roughly linear dependence on the number of laser shots. These experiments constitute a base for deeper clinical investigations. |
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| Keywords: | excimer laser ablation poly(methyl methacrylate) optical measurements ophthalmology |
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