The r₂₂electro-optic coefficients in indium-doped congruent lithium–niobate crystals

Electro-optic properties of singly and doubly doped lithium niobate crystal by rare earth elements for optoelectronic and laser applications

“…Except the contributions of Du et al [56,57] on LN crystals doped with Er 3+ ions, no work has been devoted to the study of the dielectric and electrooptical properties of crystals doped or co-doped with others rare-earth elements as Er 3+ , Yb 3+ and Ho 3+ as function of the concentration and of the structural properties. In a previous work [41], by EO and dielectric measurements it was shown that In 3+ doped congruent LN crystals present a smaller optical damage, for a concentration threshold equal to 1.7 mol%, i.e. about 3 times lower than that of Mg 2+ doping [36,58,59].…”

“…when the polarizability of Nb ions is slightly influent, the lattice deformability, mainly due to the deformability of the oxygen octahedron, will have a straightforward effect in the change with dopant concentration of the EO properties. Based on this model, the large changes in the EO properties observed in pure LN [29] with the composition or in doped LN with Zn, Mg and Zr dopant [22,23,50,53] have been explained as well as the small changes in Hf or In doped LN [41,45,57]. Thus, in the current EO characterizations of LN doping or co-doping with rare earth elements, the dopants concentrations are in a range at relatively low level and dopant ions do not largely affect the EO coefficients as they do not significantly affect the stiffening of the LN lattice.…”

“…On contrary of the numerous functional properties for divalent and tetravalent-doped LN crystals available in literature as mentioned above, only few studies mentioned the doping of LN with trivalent ions such as Sc 3+ and In 3+ [39,41,45,54,55]. Except the contributions of Du et al [56,57] on LN crystals doped with Er 3+ ions, no work has been devoted to the study of the dielectric and electrooptical properties of crystals doped or co-doped with others rare-earth elements as Er 3+ , Yb 3+ and Ho 3+ as function of the concentration and of the structural properties.…”

“…A large number of dopants with a large concentration range can dope congruent LN and it is possible to combine the properties straightforwardly associated to the dopant with the good electro-optic (EO), acousto-optic and non-linear optic properties of LN [29][30][31][32][33][34]. Among existing possible dopants for LN crystals, some researches point out that divalent ions such as Mg 2+ [1,3,4,35,36] and Zn 2+ [4,37,38], trivalent ions such as Sc 3+ [39,40] and, more recently, In 3+ [41], and finally tetravalent ions as Hf 4+ [31,32,[42][43][44][45] and Zr 4+ [46][47][48][49][50][51] can improve the optical damage resistance of LN crystals for specific concentrations. Compared with the Mg doped congruent LN crystal with 6 mol% corresponding to the damage threshold concentration, crystals doped with Hf 4+ and Zr 4+ present a threshold at around 2 mol% for which a comparable photorefractive resistance is achieved [43,46,50,52,53].…”

Composition dependence of the electro‐optic properties of iron‐doped lithium niobate crystals mounted as bulk modulator

“…The qualification of the electro‐optic properties of pure or doped LN crystal mobilizes many teams since many years and until now in connection with the improvement of the qualities of the obtained crystals, thanks to advances in growth techniques allowing new and more efficient applications. The electro‐optic (EO) effect was studied in pure LN crystal and in LN crystals doped or co‐doped with various dopants as one can see in the following set of references . A special mention can be made for the EO studies relative to iron‐doped LN crystals as iron exists in LN structure under two‐valence state, Fe 2+ and Fe 3+ , depending on the composition, the growth process, and the postgrowth treatments (reduction or oxidation annealing).…”