Here we report the synthesis of (Tm + Ta) co-doped TiO₂ ceramic by SSR method. Grain effect (EPDD), grain boundary effect (IBLC) and electrode effect all contributes to the colossal permittivity (CP) in (Tm + Ta) codoped TiO₂ ceramics.

Terahertz (THz) technology is an emerging field that is promising for future applications. Nonlinear optical (NLO) materials can effectively convert incident light into the THz frequency range using optics methods. Ionic-type organic π-conjugated NLO crystals containing electron donor-π-acceptor motifs have long attracted attention for their possibility to achieve large nonlinear optical coefficients. In this paper, an overview of the recent progress in ionic-type organic NLO crystals for highly efficient THz wave generation is presented. The substitution design strategies of cations and anions, for increasing optical nonlinearities and reducing absorptions in different structure series, are summarized. In addition, the progress in crystal growth and their THz output performance are also discussed.

We investigated the nonlinear optical properties of new BaAlBO₃F₂(BABF) crystal. The high quality BABF is nonhygroscopic and possesses a moderate birefringence suitable for UV light generation. On the basis of its refractive index dispersion curves, it is inferred that BABF has great potential applications nonlinear optical material, notably for UV light generation at 355nm. In order to characterize its nonlinear optical properties, BABF samples were cut an oriented in phase matching conditions The optical conversion efficiency from 1064nm to 532nm was investigated for the first time: up to 49.0% were achieved. The external angular acceptance bandwidth of SHG and THG for 1064nm pump light was measured.

We demonstrate high-efficiency ultraviolet (UV) laser generation in a nonlinear optical crystal $\mathrm{Ba}\mathrm{Al}\mathrm{B}{\mathrm{O}}_3{\mathrm{F}}_2$ (BABF); $355\mathrm{nm}$ UV light was generated by using a type I BABF crystal as a sum-frequency mixing of the fundamental light and the second harmonic from a picosecond Nd:YAG laser operated at a repetition rate of $10\mathrm{Hz}$ with a pulse duration of $20\mathrm{ps}$. An output of $0.635\mathrm{mJ}$ for the third harmonic was obtained. The conversion efficiency was 26.4%. As far as we know, it was the first time that third-harmonic generation in BABF was achieved. Obviously, the BABF crystal is a promising UV nonlinear optical material because of its relatively large nonlinear coefficient and nonhygroscopicity.

${\mathrm{BaAlBO}}_3{\mathrm{F}}_2$ (BABF), a newly developed nonlinear optical (NLO) crystal, was fully investigated for high-power harmonic generation of UV light. This was performed after successfully growing high-quality single crystals in the $\mathrm{LiF}–{\mathrm{B}}_2{\mathrm{O}}_3–\mathrm{NaF}$ flux system. Thermal expansion, specific heat, transmittance spectrum, nonlinear optical coefficients, and laser damage threshold were measured. High-power NLO experiments were also conducted for what we believe to be the first time for BABF crystals. Because BABF is absolutely not hygroscopic, the appealing physical, chemical, optical, and NLO properties make BABF a promising NLO crystal for practical application in high-power UV light generation.

A new rare earth ternary iodate, Ce ₂ I ₆ O ₁₈ , has been synthesized by a high temperature hydrothermal method with homemade alloy reactor equipment.