Degenerate four-wave mixing measurements were made on several Nd3+-doped laser materials by resonantly pumping the Nd3+ ions. The dominant contribution to the signal under these conditions is associated with the difference in polarizabilities of the Nd3+ ions in the metastable state versus the ground state. Absolute measurements of the signal strengths imply a laser-induced polarizability change of the order of 0.01–0.05 Å3. The results indicate that, for the case of a single-shot laser amplifier system, the beam distortion induced by this population-induced change in the refractive index is comparable with the distortion arising from thermal effects.
© 1989 Optical Society of America
Original Manuscript: May 15, 1989
Manuscript Accepted: August 8, 1989
Published: November 1, 1989
Richard C. Powell, Stephen A. Payne, L. L. Chase, and G. D. Wilke, "Index-of-refraction change in optically pumped solid-state laser materials," Opt. Lett. 14, 1204-1206 (1989)