Yb-doped inorganic crystals have attracted great attention in both basic and applied research, and the quest for suitable crystal hosts and understanding the corresponding crystal field environments are still worth studying in laser application. In this context, inclusion-free RbTiOPO 4 :Ta:Yb (RTP:Ta:Yb) single crystals with dimensions up to 3 × 30 × 15 mm 3 were grown by top-seeded solution growth method under optimized growth conditions. The good crystalline quality of the as-grown RTP:Ta:Yb crystals were confirmed by X-ray diffraction rocking curve. The chemical compositions of the crystals were determined through electron probe microanalysis (EPMA). The results showed that the Ta distribution coefficient is 0.90−1.28, and the Yb distribution coefficient is 0.13−0.37. Double doping of Ta 5+ ions can effectively increase the concentration of Yb 3+ ions in the RTP crystal, and the concentration of Yb 3+ ion in RTP crystal can reach 1.26 × 10 20 atom/cm 3 . The influence of Ta and Yb dopants on the electronic structures of RTP crystals was studied using high-resolution X-ray photoelectron spectroscopy (XPS), and the chemical strengths of Ti−O and P−O bonds are related to the binding energy difference. RTP:Ta:Yb crystals exhibit excellent transparent performance in the wavelength range of 0.35− 4.5 μm, and the transmittance is about 83%. Photoluminescence spectra show five emission peaks of Yb 3+ in crystals, and the main emission peak is located at 972 nm. Two different coordination sites for Yb 3+ were observed, and their energy levels were determined in the crystal field of the RTP:Ta structure. Furthermore, the crystal field strengths of Yb 3+ in different host crystals associated with their distorted coordination environments were evaluated and discussed in detail. The results demonstrate that the RTP:Ta:Yb single crystal endowed with high crystal field strength and good luminescence property is suitable for laser application.
RTP crystals doped with four different Ta concentrations were grown by high-temperature solution method. Ta dopants changed the growth habit of RTP and the (100) faces were more developed than the other crystal faces. The chemical composition and electronic structure were analyzed using Electron Probe Microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS). Ta elements could easily incorporate into RTP crystals from the melt due to the large distribution coefficient. As Ta content increased, the Rb 3d, Ti 2p, P 2p, O 1s XPS spectra showed a shift towards higher binding energy. The relative Ta atomic concentration in RTP:Ta crystals was calculated and it was determined that the molar ratio between Ta and Ti was higher than the nominal ratio. The thermal properties and SHG efficiency were also studied. Ta dopants decreased the transition temperature from the orthorhombic RTP phase to the cubic RTP phase and increased the decomposition temperature of the cubic RTP phase. When the Ta concentration increased to 9 mol%, the specific heat of the doped crystal was 1.5 times that of pure RTP crystal at 300 C and SHG intensity was improved by 59% when compared with pure RTP. The results show that Ta doping is helpful for improvement of SHG efficiency and increasing resistance to laser irradiation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.