Portuguese-Spanish Collaboration on LiNbO 3
- PDF / 249,644 Bytes
- 2 Pages / 576 x 777.6 pts Page_size
- 53 Downloads / 218 Views
earth-ion sites in LiNbO3, and atomic relaxation of, and around, the impurity, and assess the relevance of this information for the photorefractive response and lasing action of active impurities (Nd, Er, Cr). • Study the effects deriving from impurity concentration, such as formation of impurity aggregates and precipitated phases. • Study the interaction between different impurities, in particular, the effect of heavy Mg co-doping on the location behavior of impurities, and correlate these finding with the physical properties of the materials. It is well-known that Mg codoping markedly inhibits the photorefractive response of LiNbO3. • Study the microstructural changes induced by ion-implantation and protonexchange as methods for producing optical waveguides, and the effects on impurity behavior. The program was initially supported under the Portuguese-Spanish Bilateral Cooperation framework (Accion Integrada NH MAT88/431) and later partially financed by a NATO grant (NH CRG.890934). The program is going well and a number of new and relevant results have already been obtained. The lattice locations of several transition metals (Hf, Ti, Fe, Ta) and rare-earths (Eu, Nd, Er) on congruent LiNbO3 and LiNbO3 co-doped with Mg have now been ascertained.1 4 The Li-site occupancy of Fe needs research—a controversial issue for many years, and relevant to the physical mechanisms of the photorefractive effect. Of key importance for waveguide preparation by Ti-indiffusion is the result of Ti substituting for Li. As a general rule, transition metals tend to occupy Li-sites probably as a consequence of
Portuguese-Spanish Collaboration on LiNbOs J.C. Soares and F. Agullo-Lopez Since 1987, an intensive PortugueseSpanish collaboration program has been developed on microstructural characterization of LiNbO3 by nuclear (ion-beam and hyperfine interaction) techniques. The collaboration involves the Department of Applied Physics of the Universidad Autonoma de Madrid, on the Spanish side, and the Center of Nuclear Physics and the Department of Physics of LNETI, on the Portuguese side. The combined effort of the two latter institutions is now channeled through the recently created Center for Materials Characterization and Processing. LiNbO, is an important material for optoelectronic applications, including light modulation, microwave filters, frequency doublers, and those applications based on the photorefractive effect. Photorefractive applications, still at the laboratory level, include holographic information storage, coherent beam amplification, beam deflectors, and applications relying on the production of phase-conjugated beams by four-wave mixing. LiNbO3 is particularly useful for optical information processing, optical interconnects, associative memories, and neural net implementations. These applications involve bulk LiNbO3, but mostly waveguide structures fabricated in LiNbO3 substrates. Recently the development of efficient waveguide lasers on ion-implanted and proton-exchanged waveguides has opened a new field whose final ob
Data Loading...
