We investigated the optical properties of La2Zr2O7 transparent ceramics and found that it showed abnormal partial dispersion. The origin of the abnormal partial dispersion was also investigated by measuring the vacuum ultraviolet reflectance and infrared absorption and by performing first‐principle calculations. All the measurements and calculations were also performed on LaAlO3–Sr(Al,Ta)O3 and Ba(Zr,Mg,Ta)O3 transparent ceramics, which showed normal dispersion, for comparison purposes. A comparison of the measurements and calculations with the numerical investigations carried out using a dispersion equation indicated that a weak intensity of absorption of La2Zr2O7 in the high energy region (20–30 eV) was thought to be the predominant reason for the abnormality. In addition, a narrower bandwidth of the O‐2p band of La2Zr2O7 resulted in a high intensity of absorption around 10 eV, which in turn resulted in a relatively low ratio of the intensity of absorption between 20 and 30 eV to the intensity of absorption around 10 eV. This narrower bandwidth of O‐2p was thought to augment the abnormality of La2Zr2O7.

Nd3+-ion doped Ba(Mg,Zr,Ta)O3 ceramics is introduced as a new gain crystalline materials for lasers and laser amplifiers. By pumping laser-diode radiation at 300 K its CW stimulated emission at 1.0754 μm wavelength was recorded. Some optical, spectroscopic and mechanical properties were measured as well.

We investigated the crystal structures and optical properties of Ba(M,Mg,Ta)O3, Ba(M,Zn,Ta)O3, and Ba(M,Mg,Nb)O3 (M=Ti, Sn, Zr, and Hf) transparent ceramics. Tetravalent cation substitution resulted in a reduction in the 1:2 order structure of the B‐site of the parent perovskites; this in turn led to an increase in the transmittance of the ceramics. There was an increase in the refractive index of Ba(Mg1/3Ta2/3)O3 due to Ti, Zr, and Hf substitution at the B‐site; the refractive index was particularly high in the case of Ti substitution. Furthermore, Ti substitution resulted in a significant decrease in the Abbe number of Ba(Mg1/3Ta2/3)O3. The refractive index of the perovskites was calculated with high accuracy using the Gladstone–Dale relation. We hypothesize that the Abbe number of perovskites is dependent on its band‐gap energy.

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