Ion implantation is an attractive method for writing optical circuits for use in integrated optics. In LiNbO3 it is shown that there are large changes produced in both refractive indices n0 and ne by the energy deposited in nuclear collisions between the implanted ions and the lattice. The process is insensitive to ion species and at 300 K a universal curve exists for the decrease of n0 as a function of deposited energy by nuclear collisions. Saturation changes of −6% occur at 300 °K, and larger values are noted for 77 K implants. The saturation condition is reached after the deposition of ∼1022 keV cm−3 from the ion beams. Because the indices are reduced, ion beams have been used to write low index boundaries to define waveguiding regions. By using energetic light ions (e.g., 2-MeV He+) negligible change is produced in the surface layer where the energy loss is primarily electronic and thus the low index region is formed deep within the solid. The computed and measured mode characteristics are in good agreement. The guides show complex annealing characteristics but absorption losses are negligible after annealing at 200 °C. Guiding action exists after heat treatments up to some 400 °C. The surface layers retain crystallinity and electro-optic properties; as a demonstration of this we report results from three-dimensional modulators formed by helium-ion implantation.

The lattice location of deuterium has been investigated by channeling in fcc, hcp, and bcc metals. Implanted deuterium is studied in the range 15 K up to the release temperature and its site is compared to that of dissolved deuterium (α phase). After implantation, the octahedral and tetrahedral sites are distorted and deuterium can be displaced inside these cells. This distortion explains why implanted deuterium occupies a displaced site within the tetrahedral cell in bcc metals and not the pure tetrahedral site as for dissolved deuterium. The vacancy-deuterium interaction cannot account for all the experimental results. The trapping of implanted deuterium is described in terms of the stress induced by extended implantation defects.

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Nearly ’’stoichiometric’’ amorphous silicon carbide films were prepared by the reactive sputtering of a silicon target in a gaseous mixture of Ar, CH4, and H2 (or D2). The use of the 1H (11B, α)αα nuclear reaction and infrared transmission measurements shows that controlled amounts of hydrogen can be incorporated in the films during deposition. The hydrogen content has a dominant effect on the density of the films, its optical gap, and its refractive index. The films could be well described as a polycarbosilane, made of CHn, SiH, and SiC groups. Moreover, 11B bombardment induces a decrease of the hydrogen content and a drastic change in the bonds of the polycarbosilane. In conclusion, we show that reactive sputtering is an alternative to the glow discharge technique previously described by W.E. Spear to obtain amorphous silicon carbide.