Instability of moving gratings in photorefractive crystals

Fundamental characteristics of space-charge waves in photorefractive sillenite crystals

“…For the experimental parameter regions considered in the present paper, which are close to the ones used typically in subharmonic generation, the quality factor assumed a value of 4-5. Whether 4-5 is large enough to be considered much larger than 1, which is one of the basic assumptions in the theory of subharmonic generation, [1][2][3]8,9 is hard to tell. At first sight, a quality factor of 4-5 seems to push the theory close to the limit of applicability, but only detailed investigations of each individual case will be able to judge this question accurately.…”

“…Our brief review of the linear space-charge wave theory is based on the pioneering formulation by Sturman et al 2,3 The principal setup that we have in mind is shown in Fig. 1.…”

“…It was introduced by Sturman et al [1][2][3] and provided a whole new way of describing and understanding the dynamics of space-charge field generation in photorefractive crystals.…”

“…2,3,[6][7][8] One of the main assumptions in this theory is that the quality factor, which is the ratio of the eigenfrequency to the eigendamping, for the space-charge waves is much larger than 1. However, in spite of the large effort in obtaining agreement between theory and experiment, 3,[9][10][11][12] only a few investigations of the magnitude of the quality factor of the space-charge waves have been performed.…”

Space-Charge Wave Effects in Photorefractive Materials

“…This theory includes the basic properties of the eigen-modes, the thresholds and increments of the instability for the DC and AC excitation methods, as well as explanation of the main experimental facts. Its most advanced version is presented in [28,31]. The link to the early semiconductor papers, including the one relevant to the parametric excitation [32], was also established at this time.…”