Next Generation Laser Glass for Nuclear Fusion

The stable borosilico-phosphate new base glass which has good chemical durability, low ex-pansion coefficient, low nonlinear refraction index and can dope high concentration of dopant has been developed. Yb3+-Er3+ codoped borosilico-phosphate glass probably is candidates for economical nuclear fusion system pumping by diode laser because it can satisfy the require-ments of K. Naito (Osaka Univ.) for economical nuclear fusion system which are (a) a thermal shock parameter large than 3 W/cm, (b) saturation parameter of -10 J/cm2, (c) fluorescence lifetime longer than 4 ms, (d) a nonlinear refraction index small than 3 × 10-13 esu. The strong fluorescence intensity in Yb3+-Er3+ codoped borosilico-phosphate glass at 1.54 μm also can be used for eye safe range finder laser. The Yb3+ doped special phosphate glass which has a high concentration of modifier was developed. It also may be used for economical nuclear fu-sion system since it has some advantages below: a) the lifetimes are almost 5 times longer than Nd3+ doped phosphate glass (LHG8) which is using for nuclear fusion system, b) the emission intensities are stronger than LHG8, c) the emission wavelength are close that of LHG8. The energy transfer and energy backtransfer in Yb3+-Er3+ and Yb3+-Nd3+ systems were in-vestigated.