Theory of two-center transport in photorefractive media for low-intensity, continuous-wave illumination in the quasi-steady-state limit

Wavelength dependent effective trap density in CdTe: evidence for the presence of two photorefractive species

“…It is possible to get a feeling of the parameter accuracy that can be obtained from equation (1) and a given data set using a simple and general approach [6]. It consists of simulating a data set by using the theoretical function and a random number generator which imitates the known error distribution of each data point.…”

“…Recently a new evolution of the photorefractive model appears [1], it takes into account two deep defects both coupled to both conduction and valence bands. The model established analytical expressions for the space charge field and showed that wavelength dependent charge redistribution between the two defects was possible.…”

“…[1]. First we limit ourselves to the case of the variation of the steady state space charge field with the grating spacing in the case where no external electric field is applied.…”

“…[1], using the approximation of large diffusion lengths classically used in semiconductors, to show that the expression of the gain can be reduced to an expression of the form of equation (1) with new expressions for ξ 0 and k 0 2 that we derive. In every step of the calculations we compare the numerical results obtained with our expressions to the ones obtained without approximation with the general expressions of reference [1] (after correction of a typographical errors in formula (45) of Ref. [1]) to validate our expressions and our results.…”

“…With this new experiment we not only deduce a more accurate value of the effective trap density, but also find that N eff is different for 1.06µm and 1.55µm. In order to explain this wavelength dependence we use the photorefractive model with two photoactive traps developed by Bashaw [1], and show that this model can perfectly explain this variation of N eff with wavelength.…”