Excitation dynamics of cerium in niobate crystals

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• 作者：Liu ; Huimin ; Wang ; Yanyun ; Jia ; Weiyi ; Fernandez ; Felix
• 关键词：Excitation ; Cerium ; Niobate ; Wave-mixing ; Grating
• 刊名：Journal of Alloys and Compounds
• 出版年：1997
• 出版时间：March 20, 1997
• 年：1997
• 卷：250
• 期：1-2
• 页码：360-363
• 全文大小：297 K

文摘

Transient gratings have been observed in Ce³⁺-doped SBN(Sr_xBa_1−xNb₂O₆) and KNSBN (potassium–sodium SBN) niobate crystals by picosecond-pulse, two-photon excitation using degenerate four-wave-mixing (DFWM) in the case where the C-axis is perpendicular to the grating vector. The charge-carriers produced in the conduction band are responsible for the observed coherent signal associated with the third-order nonlinearity, while a post-coherent, slow signal is due to the temporal lattice distortion associated with formation of Nb⁴⁺-hole polarons. Following excitation of the niobate host, energy transfer between host and rare-earth ions occurred, resulting in the excited state of cerium ions being populated and cross-luminescence from host to Ce³⁺ being observed. This excitation mechanism was also verified by a fluorescence study.