Watt-level narrowband nanosecond pulsed laser source at 6.15 μm and 6.45 μm for biomedical applications based on ZGP OPO in a non-planar resonator

Certain biomedical applications, such as effective tissue ablation, require good beam quality and spectrally narrow emissions at wavelengths greater than 6 μm. Pulsed laser sources with the desired parameters in this spectral region are still limited and are mostly based on expensive, complex free electron lasers. However, optical parametric oscillators (OPOs) offer a compact alternative solution. In a non-planar cavity, we use an OPO with a ZGP nonlinear crystal that is pumped by a nanosecond-pulsed Ho:LLF laser (2.06 μm) to produce narrowband emissions at approximately 6.15 μm and 6.45 μm. In a preliminary experiment with intracavity etalons, we achieved an output power of more than 1.5 W above 6 μm, with a significantly narrowed emission bandwidth of the order of 10 nanometers.