Nd/sup 3+/ versus Yb/sup 3+/ solid-state lasers at 1 micron

Summary form only given. Yb/sup 3+/ solid-state lasers operating at 1-/spl mu/m wavelength offer some significant advantages relative to 1.06-/spl mu/m Nd/sup 3+/ solid-state lasers. These advantages include smaller quantum defect for lower heat dissipation and greater slope efficiency, simpler energy level structure for reduced parasitic effects, and longer upper state lifetimes for better utilization of diode pump sources. However, these advantages are offset by a significant disadvantage, which is quasi-three-level operation at room temperature compared with the four-level operation in Nd/sup 3+/ lasers. Additionally, Yb/sup 3+/ lasers generally have lower gain cross section than Nd/sup 3+/ lasers, which may be an advantage or disadvantage depending on the application, and generally have broader absorption features so as to relax spectral requirements of diode pump sources.