Steady holographic gratings formed in photorefractive materials: influence of material parameters

An approach previously developed by M. Carrascosa and F. Agullo-Lopez (ibid. vol.QE-22, p.1369-75, 1986) to deal with the erasure kinetics of holographic gratings in photorefractive materials is extended to the problem of writing. The explicit inclusion of the donor concentration in the photovoltaic drift term allows for a more rigorous analysis of its role. The steady-state solution for arbitrary transport length of the carriers has been obtained under the conditions of a small ripple of the light interference pattern. One main feature of the solution is that the light-induced charge field depends on the photovoltaic transport length L_ph, the carrier mobility μ, and the retrapping constant λ, through the sole factor X=L_phλ/μ. Therefore, X is a relevant figure to evaluate the performance of a photovoltaic photoreactive medium