Undoped and iron doped Bi12SiO20 crystals as optical limiters

This paper reviews the potential of photorefractive single crystals for optical limiting applications and highlights the optical limiting characteristics of undoped and iron doped Bi12SiO20 (BSO), a photorefractive single crystal belonging to Sillenite family. The contribution of two-photon absorption from two channels: first from valence band to conduction band and the other from an extrinsic silicon-vacancy to conduction band assisted by charge carrier absorption from the trap states of BSO is presented. These processes lead to highly effective nonlinear absorption across the visible region of the electromagnetic spectrum. The specific role of iron doping in enhancing the effective nonlinear absorption by charge carriers as well as intraband absorption for ns laser pulses at three different excitation wavelengths of 532, 600 and 683 nm is discussed. © Anita Publications. All rights reserved.