STRUCTURE AND NONLINEAR-OPTICAL PROPERTIES OF LANTHANIDE BORATE GLASSES

The third-order nonlinear optical susceptibility, chi((3)), of lanthan ide (lanthanum, praseodymium, neodymium, and samarium) berate glasses has been measured by the third harmonic generation method. The structu re of the present glass system has been studied by infrared and Raman spectroscopic methods, The network structures of the present Ln(2)O(3) -B2O3 glasses have been confirmed to be basically similar to each othe r, Praseodymium, neodymium, and samarium berate glasses exhibit chi((3 )) values that are larger than lanthanum berate glasses, because of th e optical resonance effect, in accordance with the f-f transition, Esp ecially, the chi((3)) value for 30Pr(2)O(3).70B(2)O(3) glass is 1.8 x 10(-12) esu, which is a factor of similar to 60 larger than that of Si O2 glass. This striking enhancement of chi((3)) is mainly attributed t o the large transition moment to the first excitation state.