Lattice damage and expansion in RbTiOPO4 crystals induced by carbon ion implantation

In this work, we report on the lattice damage and expansion in RbTiOPO4 induced by carbon ion implantation over a range of fluence from 2 × 1013 to 5 × 1013 ions/cm2. The samples were analyzed by means of Rutherford backscattering channeling spectrometry using both 1.4 MeV and 2.5 MeV He+ ions at a backscattering angle of 170°. The crystal lattice damage and strain of RbTiOPO4 samples with different fluencies were studied using the high resolution X-ray diffraction. The lattice expansion induced by ion implantation in the channel waveguide was measured by atomic force microscopy. The RbTiOPO4 waveguides formed by ion implantation keep perfectly transparent as shown in the transmission spectrum, indicated that few color centers remain in the ion implanted region after annealing. Surface indices nx, ny and nz of the samples as a function of ion fluence were studied. The relationship between concentration of displacements per atoms and effective refractive indices in RbTiOPO4, KTiOPO4 and KTiOAsO4 “barrier + well-enhanced” waveguides was investigated.