Determination of the absorption cross section of dopants in lithium niobate crystals.

A method is presented to acquire the absorption cross sections of dopants in photorefractive lithium niobate crystals utilizing doubly doped samples. The absorption cross section of one dopant must be well known. By illumination with ultraviolet light, electrons are transferred from one centre to the other. From the changes of the absorption spectra, the absorption cross section of the centre under investigation is deduced. For a wavelength of λ = 577 nm the absorption cross section of Mn(3+) is determined by this method to be σ(Mn(3+),577 nm)(o) = (9.2 ± 1.3) × 10(-19) cm(2) for ordinarily polarized light. The described method can be adapted to other dopants and host materials.