Coherent control of two photon absorption of Pr3+ ion by shaped ultrashort laser

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 Pr3+ ion system is enhanced by a factor of 12.3 by a \pi-phase step scanning of ultrashort laser pulses. T