Li+ Charge Compensation-Induced Enhancement of Spectral, Mechanical, and Thermal Properties in Cr3+-doped Ca3(VO4)2 Single Crystals

This paper presents a method that employs charge compensation to effectively enhance the spectral, mechanical, and thermal properties of Cr 3+ : Ca 3 (VO 4 ) 2 (Cr:CVO) crystals. Due to doping with heterovalent ions, a significant number of oxygen vacancies are present in the Cr:CVO crystals, resulting in strong self-absorption and suppression of emission at 842   nm. To address this issue, Li + ions were introduced as charge compensators. When the concentration of Li + ions reached 5 at%, self-absorption was most effectively suppressed, and the emission at 842   nm was significantly enhanced. Additionally, the mechanical and thermal properties of the crystal are significantly improved. The XPS research results indicate that changes in the color, spectra, and physical properties of Cr:CVO crystals primarily depend on the relative concentration of oxygen vacancies within them. Both annealing and the introduction of Li + ions effectively reduce the high concentration of oxygen vacancies in Cr:CVO crystals. However, the strategy of Li + ion charge compensation is more effective than annealing in comprehensively enhancing the overall performance of Cr:CVO crystals. This study presents an effective strategy for defect regulation and performance optimization in Cr 3+ -doped oxide laser crystals.