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Ultrafast laser surgery probe for bone tissue microsurgery

We present an ultrafast laser surgery probe for bone tissue microsurgery. A custom miniaturized CaF2 mitigated the strong multiphoton absorption observed in our previous ZnS-based design while providing tighter beam focusing over a larger ablation field-of-view. The objective produced a beam waist radius of 1.71 μm covering a 130×130 μm2 scan area, delivering fluences >8 J/cm2 at the tissue surface at 53% transmission efficiency. The entire opto-mechanical system, enclosed within a 14 mm diameter metal housing with a 2.6 mm probe tip, exhibited material removal rates >0.1 mm3/min in bovine cortical bone. We performed simulations when using a high-power fiber laser and found that material removal rates >40 mm3/min could be achieved through selection of optimal laser surgery parameters. The device can serve as a clinically viable solution for minimally invasive spinal surgery applications.