Generation of a simultaneous orthogonally polarized dual-wavelength Raman laser with power ratio tunability by a single hexagonal crystal: Cs2TeMo3O12.

A new generation of orthogonally polarized dual-wavelength lasers was demonstrated using a dye mode-locked neodymium-doped yttrium aluminum garnet laser for the first time. With a hexagonal Cs2TeMo3O12 as the Raman medium, efficient dual-wavelength stimulated Raman scattering was obtained at 1175 and 1154 nm with similar output power, corresponding to the stretching vibration of Mo-O and the asymmetric stretching vibrations of Mo-O and Te-O groups, respectively. The power ratio of two Raman components can be flexibly adjusted by tuning the polarization of the incident laser, which can be tuned from 0% to 100%. Laser sources with such a small wavelength separation could prove interesting for the difference-frequency generation of terahertz waves in the 4.6 THz range. Our study provides a simple and flexible method to achieve a promising dual-wavelength laser source in orthogonal polarization by Raman-based nonlinear frequency conversions.

Shedding Light on the Intrinsic Characteristics of 3D Distorted Fluorite-Type Zirconium Tellurite Single Crystals.

Transition-metal tellurites have motivated growing research interest in both fundamental and applied chemistry, and the corresponding single crystals could serve as rich and fascinating platforms to regulate, explore, and elucidate the intrinsic characteristics of different structures from 0D to 3D architectures. In this context, a zirconium tellurite (namely, ZrTe3O8) single crystal featuring a 3D distorted fluorite-type structure with a size of 35 × 32 × 21 mm3 was successfully harvested by the top-seeded solution growth (TSSG) technique. The X-ray diffraction rocking curve reflects that the crystallinity of the as-grown ZrTe3O8 crystal is quite perfect with a small full-width at half-maximum (fwhm) value (∼39 arcsec). The temperature dependence of the thermophysical properties of the ZrTe3O8 single crystal has been systematically analyzed. The ZrTe3O8 single crystal exhibits a wide transparency window, as the UV and IR absorption cutoff edges are respectively 278 and 7788 nm. The refractive indices over the region from the visible to the near-IR have been determined and manifested relatively large values of 2.0889-2.0370 over a wavelength range of 632.8-1553 nm. Furthermore, the fundamental physical characteristics of the ZrTe3O8 single crystal associated with its distinctive 3D framework structure have been evaluated with density functional theory (DFT) calculations.

Rational Design of a LiNbO3-like Nonlinear Optical Crystal, Li2ZrTeO6, with High Laser-Damage Threshold and Wide Mid-IR Transparency Window.

With existing and emerging technologies urgently demanding the expansion of the laser wavelengths, high-performance nonlinear optical (NLO) crystals are becoming indispensable. Here, a prospective NLO crystal, Li2ZrTeO6, is rationally designed by the element substitution of Nb for Zr and Te from LiNbO3, which has been recognized as one of the most commercial NLO crystals. Li2ZrTeO6 with R3 symmetry inherits the structural merits of LiNbO3 (space group R3 c) and thus meets the requirements for NLO applications, including noncentrosymmetric crystal structure, moderate birefringence, and phase-matchability. Moreover, it can be exploited to achieve more outstanding optical damage resistant behavior (>1.3 GW cm-2), exceeding 22 times that of LiNbO3, which is more suitable for high-energy laser applications. Notably, this compound displays the widest IR absorption edge (7.4 µm) among all of the noncentrosymmetric tellurates reported so far. These excellent attributes suggest that Li2ZrTeO6 is a promising candidate for providing high NLO performance. The substitution of Nb for Zr and Te from LiNbO3 demonstrates a viable strategy toward the rational design of NLO crystals with anticipated properties.

Biaxial crystal ß-BaTeMo2O9: theoretical analysis and the feasibility as high-efficiency acousto-optic Q-switch.

The high efficiency acousto-optic modulators become indispensable in photonics and optoelectronics for the pulse generation and signal modulation in optical display and telecommunications. In this paper, the validity and feasibility of the biaxial crystals as acousto-optic mediums have been theoretically analyzed and confirmed by experiments using a biaxial crystal of ß-BaTeMo2O9. The diffraction angle and diffraction efficiency of the ß-BaTeMo2O9 acousto-optic Q-switch are determined to be 1.420° and 78.1%, which are comparable with that of TeO2 acousto-optic modulator at the identical operating wavelength of 1064 nm and 100 MHz, respectively. The minimum of the modulated pulse width can be achieved to be 6 ns at 5 kHz with Nd:YVO4 as the gain medium. The results not only provide an excellent acousto-optic medium, but also explore the field of biaxial acousto-optic medium for device fabrications.