Agradecimentos: We acknowledge financial support from Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq and Fundação de Amparo à Pesquisa do Estado de São Paulo - FAPESP both from Brazil and from the Ministerio de Educación y Ciencia, Spain, under grant TIC2001-0605

Abstract: We analyze the mechanisms leading to a highly diffractive fixed hologram in photorefractive Fe-doped lithium niobate crystals by simultaneous self-stabilized holographic recording and compensation at moderately high temperatures. We show that a partially compensated running hologram is...

Abstract: We analyze the mechanisms leading to a highly diffractive fixed hologram in photorefractive Fe-doped lithium niobate crystals by simultaneous self-stabilized holographic recording and compensation at moderately high temperatures. We show that a partially compensated running hologram is produced during recording under this condition and discuss the performance of the process in terms of the operating temperature, the degree of oxidation ([Fe3+]/[Fe2+] ratio) of the sample, and the effect of the absorption grating arising from the spatial modulation of the Fe2+ concentration produced during photorefractive recording. We experimentally measure the evolution of the uncompensated remaining hologram during recording and the evolution of the diffraction efficiency of the fixed hologram during white-light development and show that the maximum fixed grating modulation to be achieved is roughly limited by Fe-dopant saturation. A reproducible eta approximate to 66% efficiency fixed grating was obtained on a sample exhibiting an otherwise maximum fixed eta approximate to 3% when using the classical three-step (recording at room temperature-compensating at high temperature-developing at room temperature) process

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP

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