COMPOSITION DEPENDENCE OF THE ULTRAVIOLET-ABSORPTION EDGE IN LITHIUM-NIOBATE

A convenient and fast method to determine the composition of LiNbO3 si ngle crystals consisting of a measurement of the position of the funda mental absorption edge in the near UV region is refined and extended t o the stoichiometric range. Using unsophisticated apparatus and simple reflection correction, the proposed two-parameter calibration equatio n provides an absolute accuracy of 0.1 mol % with the relative accurac y reaching an unusual value of better than 0.01 mol % for near stoichi ometric compositions. (C) 1997 American Institute of Physics.