Increased concentration of Yb3+ and high crystal field strength in RbTiOPO4:Ta single crystal with optimized growth

Yb doped inorganic crystals have attracted great attention in both basic and applied research, and quest for suitable crystal hosts and understanding corresponding crystal field environments are still worth studying in laser application. In this context, inclusion-free RbTiOPO4:Ta:Yb (RTP:Ta:Yb) single crystals with dimensions up to 3×30×15 mm3 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), and the results showed that the Ta distribution coefficient is 0.97-1.28 and the Yb distribution coefficient is 0.13-0.37. Double doping of Ta5+ ions can effectively increase the concentration of Yb3+ ions in the RTP crystal, and the concentration of Yb3+ ion in RTP crystal can reach 1.26×1020 atom/cm3. The influence of Ta, Yb dopants on electronic structures of RTP cry...