Neodymium concentration measurements in Nd:YLF laser rods: a nondestructive method

A nondestructive method for measurements of Nd(3+) concentration in Nd:YLF laser rodes is presented. The method, based on the comparison of the intensities of Nd(3+) luminescence lines to the intensities of the host matrix (LiYF(4)) Raman lines, requires the use of a micro-Raman spectrometer. The experimental conditions have been optimized and are described in detail. The investigations were performed in the concentration range 0at.%-2at.% of Nd and the calibration curve is presented. In standard use, the relative error on the results never exceeds 10%. Using this method to study the concentration gradient in a crystal is shown and the distribution coefficient of Nd(3+) in LiYF(4) is deduced.