Method of thermally drawing structured sheets

A method of drawing a material into sheet form, the method comprising the steps of:

• providing a preform comprising at least one material wherein a first transverse dimension of the preform is greater than a second transverse dimension that is substantially perpendicular to the first transverse dimension, the preform also having a third dimension that is substantially perpendicular to the first and second transverse dimensions and defining a pulling direction;
• providing a furnace having at least one heating element on at least one side of the furnace;
• energizing the at least one heating element to apply heat to the preform, without the at least one heating element physically contacting the preform, only along an exterior surface of the first transverse dimension to create a thermal gradient of decreasing temperature from the exterior surface inward along the second transverse dimension toward a plane of the preform, wherein the at least one heating element creates approximately uniform temperature distribution along the first transverse dimension;
• feeding the preform into the furnace;
• and
• drawing, by pulling in the pulling direction, the preform in such a manner that the material does not substantially deform across its first transverse dimension and deforms across its second transverse dimension while stretching the preform in the third dimension.