Machining of crystalline lithium niobate is carried out utilizing a laser
having a beam with a wavelength near the absorption edge of lithium niobate. The
laser beam is provided in pulses of short duration and at a repetition rate selected
to ablate the surface of the lithium niobate without damaging the bulk material.
Translation of the laser beam and the substrate with respect to each other can
be carried out to define a trench of a desired geometry in the lithium niobate.