Second harmonic generation from RE doped BGO waveguides

Samples of EGO doped with Tm3+, Er3+, Ho3+, EU3+, Sm3+ and Nd3+ have been i mplanted at LNT (77 K) with Hei ions for waveguide fabrication. The energy and the dose of the implantation are 2 MeV and 5 x 10(16) ions/cm(3), respe ctively. The samples have been annealed in the furnace at 250 degrees C, 35 0 degrees C, 400 degrees C and 350 degrees C for 1 h in air. The SHG intens ity improved with increasing annealing temperature, due to removal of defec ts caused by the implantation. There is a restructuring of the implanted gu ide which results in a modified crystal lattice and a greatly improved SHG. The effect increases with the difference between the radius of the RE ions and the Bi ion. The latter effect could be explained by the mismatch of io n size of the RE ion which distorts the cubic structure of EGO in the impla nted region to become slightly anisotropic, which in turn improves the SHG of BGO:RE waveguide layer. (C) 2000 Elsevier Science B.V. All rights reserv ed.