Intensities and spectral features of the <inline-formula><img src="cpb_26_11_114208_ieqn1.gif"/> </inline-formula>–<inline-formula><img src="cpb_26_11_114208_ieqn2.gif"/> </inline-formula> potential laser transition of Er<sup>3+</sup> centers in CaF<sub>2</sub>

Wang Qing-Guo^{1, 2}, Su Liangbi³, Liu Jun-Fang⁴, Liu Bin¹, Wu Feng^{1, 2}, Luo Ping^{1, 2}, Zhao Heng-Yu¹, Shi Jiao-Jiao¹, Xue Yan-Yan¹, Xu Xiao-Dong⁵, Ryba-Romanowski Witold⁶, Solarz Piotr⁶, Lisiecki Radoslaw⁶, Wang Zhan-Shan¹, Tang Hui-Li^{1, 2}, Xu Jun^{1, 2, †}