CaMoO4 single crystals doped with Dy3+ were grown from sodium molybdate flux. Their absorption and visible emission spectra and decay curves were measured at different temperatures from 10 to 298 K. The complete energy level scheme has been deduced from the low-temperature measurements. The Judd-Ofelt parametrization scheme has been applied to the analysis of the room temperature absorption spectra. The calculated radiative lifetime of the 4F9/2 state is 152±5 µs, and it is in reasonable agreement with the experimental data. The decay curves measured in the 10-170 K temperature range are not exponential and obey the Inokuti-Hirayama model for energy transfer for an electric quadrupole-quadrupole interaction in the absence of diffusion among the donors. All spectral features are strongly affected by an inhomogeneous broadening connected with the `disordered crystal' character of the title compound.

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The optical spectra of the BaY2F8:Dy3+ laser crystal have been investigated in the 5000–30 000 cm−1 range. The Judd–Ofelt parametrization scheme has been applied to the analysis of the room temperature absorption spectra. The calculated radiative lifetime of the 4F9/2 state is 1.48 ms. Decay curves of the visible emission have been measured as a function of the temperature for two different Dy3+ concentrations (0.5 and 4.4%). In the case of the diluted crystal the emission profiles are single exponential with decay times consistent with the radiative lifetime. The decay curves of the concentrated crystal are not exponential and they obey the Inokuti–Hirayama model for energy transfer for an electric dipole–dipole interaction in the absence of diffusion among the donors. The emission cross section at 575 nm has been estimated using the integral β–τ method in order to assess the potentialities of this compound as a solid state laser material in the yellow region.

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Nd:Ba 2 NaNb 5 O 15 (Nd:BNN), Nd:Ba 2 KNb 5 O 15 (Nd:BKN) and Ba 1.90 Nd 0.26 Li 0.42 Nb 5 O 15 (BNdLN) single crystals with the tetragonal tungsten-bronze (TTB) structure have been grown by means of the 'flux growth' method. The 10 and 298 K absorption and emission spectra and the room temperature decay curves have been measured and discussed in the light of the crystallographic information. The room temperature absorption spectra of Nd:BKN and BNdLN have been analysed in the framework of Judd-Ofelt theory and the λ (λ = 2, 4, 6) intensity parameters have been evaluated. The structural and emission properties of a new TB phase, Nd:Ba 2 LiNb 5 O 15 (Nd:BLN), have also been reported because they are useful in the discussion concerning the site occupancy of the active ions in these materials.

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