From CsKTaF₇ to CsNaTaF₇: Alkali Metal Cations Regulation to Generate SHG Activity**

Abstract

Inorganic metal halides play important roles in wide range of areas including fluorescence, X‐ray detection, and nonlinear‐optics. Herein, two new mixed alkali metal tantalum fluorides, CsKTaF7 and CsNaTaF7, have been obtained based on the strategy of cations regulation in A2MF7 (A represents monovalent cations and M is d0 transition‐metal cation) system by a conventional hydrothermal route. CsKTaF7 crystallizes in the centric Pnma space group, while CsNaTaF7 crystallizes in the polar Cmc21 space group and exhibits moderate and phase‐matchable NLO activity. Both halides possess large optical band gaps above 5.0 eV. The crystal structure evolution, optical properties, and detailed theory calculations of these two halides were elucidated in this work.

Centrosymmetric CaBaMF8 and Noncentrosymmetric Li2CaMF8 (M = Zr, Hf): Dimension Variation and Nonlinear Optical Activity Resulting from an Isovalent Cation Substitution-Oriented Design

“…Clearly, the SHG intensities of 3 and 4 arise with the increased particle sizes, reaching a platform at 200–250 μm, declaring the PM behavior of 3 and 4 at 1064 nm. Additionally, 3 and 4 show moderate SHG efficiencies (0.36, 0.30 × KDP) and are comparable with some halides like CsNaTaF 7 (0.2× KDP), KNa 2 ZrF 7 (0.4× KDP), and CsSbF 3 Cl (0.3× KDP) . Some strategies can further improve the SHG intensities.…”

Exploring a new short-wavelength nonlinear optical fluoride material featuring unprecedented polar cis-[Zr6F34]10− clusters

“…34,67 The birefringence (Δ n ) is calculated to be 0.08@1064 nm (Fig. 4c), which is larger than some d 0 -TM based fluorides and oxyfluorides like CsNaTaF 7 (0.01@1064 nm), 68 K 3 ZrF 4 (SbF 4 )(SbF 5 ) (0.038@1064 nm) 49 and K 8 (ZrF 6 )(Sb 2 Zr 2 F 20 ) (0.039@1064 nm). 49 The birefringence (Δ n ) is large enough for PM ability and manifests the shortest PM wavelength (400 nm) calculated in Fig.…”

From ZnF2 to ZnF2(H2O)4: Partial Substitution Achieves Structural Transformation and Nonlinear Optical Activity while Keeping Short Ultraviolet Cutoff Edge

“…The SHG signal intensity increases gradually with the increase in sample size, indicating that ZnF 2 (H 2 O) 4 is phase-matchable. This SHG intensity is larger than some NLO fluoride crystals with short UV cutoff edges, including BaZnF 4 (0.16 × KDP), SrZnAsF (0.273 × KDP), KNa 2 ZrF 7 (0.35 × KDP) and CsNaTaF 7 (0.2 × KDP) . However, this intensity is not strong compared with some excellent NLO crystals.…”

“…This SHG intensity is larger than some NLO fluoride crystals with short UV cutoff edges, including BaZnF 4 (0.16 × KDP), 58 SrZnAsF (0.273 × KDP), 59 KNa 2 ZrF 7 (0.35 × KDP) 60 and CsNaTaF 7 (0.2 × KDP). 61 However, this intensity is not strong compared with some excellent NLO crystals. Halogen ions with higher polarizability and lone pair electron cations can be introduced to enhance the SHG intensity.…”