Doped and undoped single crystal multilayered structures

摘要

Disclosed is a multilayer electro-optical material having a plurality of adjacent, single crystals of varying electro-optical properties. This material is made by a method wherein the successive layers are epitaxially grown from a molten solution of said electro-optical material optionally containing at least one dopant.;In one embodiment, such electro-optic material comprises silver thiogallate, wherein successive epitaxial layers are grown from a molten solution of silver thiogallate and potassium chloride, and which optionally includes at least one dopant. This molten solution exhibits the characteristic that, for any specific solution composition, layers having different electro-­optical properties can be obtained by cooling over the temperature range which will yield crystal growth of the composition corresponding to the desired electro-optical properties. By taking advantage of this temperature/­composition phase precipitation, multi-layers are formed by cooling first within one temperature range to form on the seed crystal substrate a layer of silver thiogallate including the dopant and then subsequently forming on this first layer a second layer of different composition varying from substantially pure silver thiogallate to silver thiogallate including at least one dopant, by cooling within a different temperature range. By successively alternating between cooling over these different tempeature ranges, multiple layers are formed with adjacent layers having different electro-optical properties.;The multi-layered structures produced by the above method can be utilized in electro-optical devices, and particularly as the tunable birefringent medium in tunable electro-optic filters.