Emission Spectroscopy of Eu-Doped CaF2 under Static and Dynamic High Pressures

The time-resolved emission spectra of the CaF 2 (Eu) crystal subjected to impact-induced shock compression in the inelastic region have been measured up to 31.6 GPa and the effect of shock and release waves on the Eu emission spectrum has been recorded. The Eu 2+ spectrum centered at ∼425 nm shifts toward the longer wavelength with a shock pressure of up to ∼15 GPa, but no further shift has been observed at higher pressures. Emission spectra under static pressure have also been measured up to 10.2 GPa and compared with those under shock compression. A blue Eu 2+ emission at ∼425 nm and a sharp orange Eu 3+ emission at ∼590 nm are observed under static pressure. A large pressure shift of ∼2.2 nm/GPa is observed for the blue emission at pressures of up to ∼10 GPa, but the orange emission spectrum hardly moves against pressure. The Hugoniot determined for the CaF 2 (Eu) single crystal is U s =5.15+1.18 U p .