文摘
We investigate the second-order fluorescence (FL) signals of Pr3+:YSO both theoretically and experimentally. For the first time, the Autler鈥揟ownes (AT) splitting effect of FL spectrum induced by itself and/or external fields and the polarization dependence of FL signals in two-level, V-level, and N-level atomic systems are observed and explained. The AT splitting distance can be modulated by the frequency detunings, power, and polarization configurations of the incident fields which are well explained by using the presented theoretical model.