Design of an ultrafast laser surgical probe towards maximum achievable MRR

The major advancements in ultrafast laser ablation technology are revolutionizing surgical precision and minimizing thermal impact compared to traditional methods. However, the primary challenge hindering widespread clinical adoption has been the slow material removal rate (MRR). Towards this gap, a compact fiber-based laser delivery system has been developed, boasting an impressive 82-fold increase in MRR over the previous femtosecond laser surgical probes. This benchtop setup utilizes a hollow-core Kagome fiber (NA≈0.02) coupled to a high-power Yb-doped fiber laser (λ=1035 nm) to deliver laser pulses onto the sample. Employing a piezo-scanned Lissajous-based beam steering mechanism, the system achieves efficient distribution of ultrashort pulses onto the target surface. Remarkably, the system maintains a high transmission efficiency of 74% while operating at peak intensities, with no components exhibiting nonlinear behavior. For a FOV scan width of 550 µm, the logarithmic relationship between the ablation depth and laser fluence was determined for two different translational velocities. The system achieved material removal rates of ~10.7 mm3 /min for the maximum applied laser fluence of 9.3 J/cm2, without initiating carbonization. Moreover, by fine-tuning laser parameters, the system can swiftly create clean-cut trenches of significant dimensions, 3 x 3 mm2 size and ~1 mm deep, mimicking conventional surgical procedures such as spinal decompression within a minute, all without carbonization or tissue damage. This remarkable achievement underscores the reliability and potential of ultrashort-laser ablation techniques for a wide array of surgical interventions.