Raman-shifted alexandrite laser for soft tissue ablation in the 6- to 7-μm wavelength range

Prior work with free-electron lasers (FELs) showed that wavelengths in the 6- to 7-μm range could ablate soft tissues efficiently with little collateral damage; however, FELs proved too costly and too complex for widespread surgical use. Several alternative 6- to 7-μm laser systems have demonstrated the ability to cut soft tissues cleanly, but at rates that were much too low for surgical applications. Here, we present initial results with a Raman-shifted, pulsed alexandrite laser that is tunable from 6 to 7 μm and cuts soft tissues cleanly-approximately 15 μm of thermal damage surrounding ablation craters in cornea-and does so with volumetric ablation rates of 2-5 × 10^-3 mm³/s. These rates are comparable to those attained in prior successful surgical trials using the FEL for optic nerve sheath fenestration.