Strong nonlinear optical response in epitaxial liftoff single-crystal LiNbO3 films

We report on optical frequency mixing in epitaxial liftoff thin films of single-crystal ${\mathrm{LiNbO}}_{\mathrm{3}}$ integrated onto heterogeneous planar glass platforms. These films are found to have a nonlinear optical response comparable to that of the bulk. Second-harmonic generation is investigated as a function of crystal orientation, ion implantation, and modal and temperature dispersion. Ion implantation-induced shifts in the refractive indices are shown to be useful for achieving phase matching.