| 摘要 |
The present invention provides a method of laser processing of materials, specifically laser induced ablation processes for laser removal of material particularly important in medical and dental applications in which the laser removal of material should be done in such a way as to not damage any of the surrounding soft or hard biomaterial. The ablation process is achieved by impulsive heat deposition (IHD) by direct and specific excitation of short lived vibrations or phonons of the material in such a way as to not generate highly reactive and damaging ions through multiphoton absorption. The heat deposition and ensuing ablation process under prescribed time and wavelength conditions for laser irradiation is achieved faster than heat transfer to surrounding tissue by either acoustic or thermal expansion or thermal diffusion that otherwise would lead to excess heat related damage. The result is that all the deposited laser energy is optimally channelled into the ablation process in which the inertially confined stresses from both photomechanical expansion forces and thermally driven phase transitions and associated volume changes constructively interfere to drive the most efficient ablation process possible with minimal damage to surrounding areas by either ionizing radiation or heat effects. By choosing a specific range of wavelengths, spatial and temporal shaping of infrared laser pulses, the energy can be optimally deposited in a manner that further increases the efficiency of the ablation process with respect to minimizing collateral damage. |
