Mid-IR laser for high-precision surgery

Abstract

We have studied the potential for using mid-IR lasers in high-precision non-traumatic surgery, validated the parameters and optical design of a tunable solid-state laser with parametric conversion of radiation to the protein absorption band (6–8 μm), and tested the key components of such a laser experimentally. A pulsed-periodic Ho3+:YLF laser (λ=2.051 μm), pumped by a Tm fiber laser (λ=1.94 μm), with pulse energies of up to 80 mJ (at a frequency of 100 Hz) and 50 mJ (at a frequency of 1000 Hz) was developed. The laser had a pulse width of 20 ns, a beam quality M2 of 1.5, and a laser optical efficiency of 30%. The radiation from the Ho:YLF laser was parametrically converted to the mid-IR (3–6 μm) using ZnGeP2 (ZGP) nonlinear crystals. The total signal + idler wave energies of up to 100 mJ at pulse repetition rates of 100 Hz (and a conversion efficiency of 40%) were achieved using a two-cavity ZGP optical parametric oscillator system and a parametric amplifier (paramp).