In the present study, various concentrations of ErF3-doped CaF2 crystals were grown using the vertical Bridgman method. The Judd–Ofelt intensity parameters for f–f transitions of Er3+ ions were determined from optical absorption spectra. The concentration dependence of the intensity parameters radiative transition probability, oscillator strength, branching ratio and radiative lifetime was also investigated. The predicted radiative lifetimes

Calcium fluoride crystals doped with YbF3 and co-doped with LiF and NaF were grown using the vertical Bridgman method. Several of rare-earth ions (such as Eu, Sm, Ho, Tm, and Yb) can be stabilized in the divalent state in the CaF2. The change of valence was attained by various methods. The optical absorption spectra reveal the characteristic absorption bands of the Yb3+ and Yb2+ ions. This means that the developed crystal growth process achieves

Calcium fluoride crystals doped with YbF3 and PbF2-, NaF- and LiF-codoped were grown using the vertical Bridgman method. Transparent, high quality, with various high Yb2+ contents in the as-grown crystals has been obtained using a special procedure. The optical absorption spectra reveal the characteristic ultraviolet (UV) absorption bands of the divalent Yb ions. Influence of the codoping with Pb2+, Li+ and Na+ ions on the absorption spectra and

Calcium fluoride crystals doped with ErF3 and PbF2 have been grown using the vertical Bridgman method. Temperature and frequency dependence of the complex dielectric constant have been measured at seven audio frequencies (1–100 kHz) over the temperature range of 150–300 K. The activation energy for dipole reorientation and the relaxation time constant has been determined from the observed relaxation processes. The effect of Er3+, Pb2+ ions and

Calcium fluoride crystals doped with ErF3 and YbF3 have been grown using the vertical Bridgman method. The real and imaginary parts of the complex dielectric constant have been measured at five audio-frequencies (1–100 kHz) over the temperature range 150–300 K. From the observed relaxation processes the activation energy for dipole reorientation and the relaxation time constant have been determined. A comparison of our results with those obtained

Temperature and frequency dependence of the complex dielectric constant give information about the relaxation processes annd permits the determination of the activation energy and the reciprocal frequency factor of the relaxation time. Pure and various concentration PbF2-doped CaF2 crystals have been grown using the vertical Bridgman method. The thin disks cut from the crystals have been X-ray irradiated. Room temperature optical absorption spectra

Calcium fluoride crystals doped with ErF3 and YbF3 have been grown using the Vertical Bridgman method. The real and imaginary part of the complex dielectric constant have been measured at five audio frequencies (1 kHz - 100 kHz) over the temperature range 150 -300 K. From the observed relaxation processes the activation energy for dipole reorientation and the relaxation time constant have been determined. A comparison of our results with those obtained