FABRICATION OF SINGLE CRYSTAL FIBERS FROM CONGRUENTLY MELTING POLYCRYSTALLINE FIBERS

摘要

This invention provides a method for conversion of congruently melting polycrystalline fibers to single crystal fibers. The method is particularly useful for production of fibers ranging from about 30 mu m to about 1,000 mu m in diameter, which are capable of infrared (IR) transmission and of functioning in nonlinear optical applications. The polycrystalline fiber is converted to a single crystal fiber by creating a melt zone near one end of said polycrystalline fiber and then causing said melt zone to travel a length of said polycrystalline fiber at least once, so that the fiber continuously melts and recrystallizes into a single crystal along the length so that such length becomes one continuous crystal. In another embodiment of the invention, the method described above is utilized to improve the surface characteristics of a single crystal. In yet another embodiment of the invention, the method disclosed above is utilized to produce a fiber comprised of a polycrystalline core surrounded by a single crystal sleeve or large grained crystal sleeve which evidences single crystal behavior. This method is particularly useful for production of fibers ranging from about 30 mu m to 1,000 mu m in diameter, which are capable of infrared (IR) transmission. If the sleeve is a sufficiently large proportion of the fiber produced, this method is particularly useful for production of fibers which may be capable of functioning in nonlinear optical applications.