Enhancing the photoluminescence and depressing the background emission are important problems in rare earth ion-doped materials. In this letter, the two-photon absorption (TPA) probability in a Pr<sup>3+</sup> ion system is enhanced by a factor of 12.3 by a π-phase step scanning of ultrashort laser pulses. This level is significantly higher than that achieved by a transform-limit pulse. However, the laser intensity of shaped pulse is reduced to 37% of the initial transform-limited pulse. In this method, the TPA probability can also be reduced to 58%. Furthermore, the effect of the shift of the intermediate energy level and the bandwidth of final states on TPA probability is discussed.
© 2013 Chinese Optics Letters
(190.4180) Nonlinear optics : Multiphoton processes
(190.7110) Nonlinear optics : Ultrafast nonlinear optics
(190.7220) Nonlinear optics : Upconversion
(320.5540) Ultrafast optics : Pulse shaping
Wenjing Cheng, Shian Zhang, Tianqing Jia, Jing Ma, Donghai Feng, and Zhenrong Sun, "Coherent control of two-photon absorption of Pr3+ ion by shaped ultrashort laser pulses," Chin. Opt. Lett. 11, 041903- (2013)