A Kagome fiber-based, high energy delivery laser scalpel system for ultrafast laser microsurgery

We present the development of a 5 mm, piezo-actuated, ultrafast laser scalpel for microsurgery with a capability to deliver energies in excess of 1 μJ per pulse. Having previously established that the maximum energy deliverable was limited by cladding damage in photonic badgap fibers, we utilized a large, 35μm cored inhibited-coupling Kagome fiber that allowed the delivery of micro-Joule energy femtosecond pulses. To maintain diffraction limited performance over the entire scan range of the piezo-actuated fiber tip, special objective lenses were developed and manufactured out of a high-refractive index Zinc Sulfide (ZnS) crystal. The probe was packaged in hypodermic 304SS stainless steel with a form factor minimizing in-line configuration. The probe’s performance was tested via metal and tissue ablation studies, characterizing highspeed ablation parameters and uniformity of ablation over the scan area. Additionally, we studied the nonlinear performance of ZnS and Calcium Fluoride (CaF 2 ) as materials for refractive optics and determined the maximum energy deliverable through our probe using these optical materials. The high energy delivery through the probe system should allow for fast and effective tissue ablation.