We report on three-dimensional bright and long-lasting phosphorescence in a Ce<sup>3+</sup>-doped Ca<sub>2</sub>Al<sub>2</sub>SiO<sub>7</sub> crystal. After we scan with a focused 800-nm femtosecond pulsed laser, the path traversed by the focal point of the laser in the crystal emits bright and long-lasting phosphorescence that can be seen with the naked eye in the dark even 10 h after the removal of the activating laser. Absorption spectra of the crystal show that defect centers have formed after the laser irradiation, and the absorption that is due to the defect centers decays with time. It is suggested that a mechanism of the long-lasting phosphorescence consists of a thermostimulated recombination of holes and electrons at traps induced by the laser irradiation at room temperature.
© 1999 Optical Society of America
Jianrong Qiu, Nobuhiro Kodama, Mitsuo Yamaga, Kiyotaka Miura, Tsuneo Mitsuyu, and Kazuyuki Hirao, "Infrared femtosecond laser pulse-induced three-dimensional bright and long-lasting phosphorescence in a Ce3+-doped Ca2Al2SiO7 crystal," Appl. Opt. 38, 7202-7205 (1999)