Ablation characteristics of menisci by various laser irradiation (193 nm-10.6 μm), pulsed and continuous wave

Abstract

The laser ablation characteristics of the procine menisci by the various laser irradiations were studied. We employed nine laser wavelengthes from ultraviolet(UV) region to infrared(IR) region, pulsed or continuous wave(cw). They were ArF(193nm in wavelength, pulsed), KrF(248nm, pulsed), XeC1(308nm, pulsed), XeF(351nm, pulsed), Ar ion UV(351nm,cw), Ar ion visible(515nm, cw), Nd:YAG(1.06pm, cw), C0(5.3pm, cw) and C02(10.6jim, cw) lasers. All laser irradiation experiments were performed in vitro with a fixed laser beam to the menisci in air circumstance. The ablation rate and damaged layer thickness were measured. In order to compare the ablation characteristics of various laser wavelengths at the same condition, the laser irradiation energy density was kept constant to 60,J/cm2/sec. The ablation rate by the energy density of 1J/cm2 and the damaged layer thickness by the energy density of 1200J/cm2 were measured. The measured menisci ablation rate by ArF excimer laser was 9.5 (ArF 9.5), (KrF 92.1), (XeCl 74.4), (XeF 2.3), (Ar ion UV 64.8), (CO 69.5), (CO2 204.9) )ig/J. The damaged layer thickness of menisci by ArF excimer laser was 119 (ArF 119), (KrF 12), (XeCl 299), (XeF 645), (Ar ion UV 860), (CO 1105), (CO2 1209) pm. This study will investigate if the ablation characteristics depends on the wavelength of lasers and on emission mode (pulsed or cw). In the case of XeC1 excimer laser irradiation experiment, the contact irradiation to menisci in the water circumstance were carried out. The ablation rate using XeC1 excimer laser in water by the contact method was almost equal to that by the non-contact method in air. The damaged layer thickness using XeC1 excimer laser in water was considerably thin compared with that by the non-contact method in air. We expect that this study for menisci laser ablation may be contribute the progress in arthroscopic laser meniscectomy.