In vitro studies of femtosecond pulse interaction with bone

Lasers utilization in biomedical areas is a growing area, in spite of the collateral thermal damage that they can cause in the surrounding tissue. The purpose of this study is to analyze, in vitro, the ablative interaction of a femtosecond and high power laser, the amplified Ti:sapphire laser (830 nm), impinging in the hard tissue, in particular, the rabbit bone tissue. A principal oscillator and an amplificator compose this laser system (CPA technique). The extracted pulses peaking at 830 nm, after the temporal compression, present 51 fs, 1000 Hz and energy of ~ 0,7 mJ. The M2 quality factor was 2.0, and the laser was focused by 20 cm focus lens. A computerized translation table x,z was also used for the movement of the samples. We determined an ablation threshold fluency of 0,54 J/cm2 and the ablation threshold intensity of 9,26 TW/cm2. Using the Optical Coherent Technique, we analyzed the ablation volume as a function of the intensity and then verified that the intensity the maximum ablation rate is found at four times the ablation limier intensity. With the SEM analysis, we observed the cavities produced with shape edges, at sub micrometric order, sharp design and high cut precision. Thermal damages were not observed in any of the samples