Nd-doped phosphate glasses for high-energy/high-peak-power lasers

The composition and properties of neodymium-doped (Nd-duped) phosphate glas ses used for simultaneous high-energy (10(3)-10(6) J) and high-peak-power ( 10(12)-10(15) W) laser applications such as fusion energy research, are rev iewed. The most common base glasses are meta-phosphates (O/P similar to 3) with the approximate composition: 60P(2)O(5)-10Al(2)O(3)-30M(2)O/MO; K/Ba o r K/Mg are typical modifiers. The spectroscopy of Nd3+ in these glasses is well understood and laser properties can be accurately determined from meas ured spectroscopic properties. The major mechanisms for Nd3+ non-radiative relaxation are reviewed and empirical expressions are presented that predic t these effects in phosphate glasses. Optical and thermal-mechanical proper ties have been measured on a number of laser glasses and can be correlated with composition. Sub-critical crack growth rates in stress regions I, II a nd III have been reported for the first time in phosphate laser grasses. Th e mechanism for Pt inclusion formation and dissolution has been studied lea ding to damage resistant (Pt-inclusion-free) laser glasses, (C) 2000 Elsevi er Science B.V. All rights reserved.