Sub-band-gap laser micromachining of lithium niobate

Laser processing of insulators and semiconductors is usually realized using photon energies exceeding the band-gap energy. This makes laser processing of insulators difficult since high photon energies typically require either a pulsed laser or a frequency-doubled continuous-wave laser. A new method is reported which enables us to do laser processing of lithium niobate using sub-band-gap photons. Using high scan speeds, moderate power densities, and sub-band-gap photon energies results in volume removal rates in excess of 106μm3/s. This enables fast micromachining of small piezoelectric structures, or simple etching of grooves for precision positioning of optical fibers.