Z-scan study of nonlinear absorption in reduced LiNbO3 crystals
Z-scan study of nonlinear absorption in reduced LiNbO3 crystals
复制标题
还原 LiNbO3 晶体非线性吸收的 Z 扫描研究
DOI：
10.1063/1.4716470
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
M. Aillerie
中科院分区：
文献类型：
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作者：
S. Kostritskii;M. Aillerie
通过开孔 Z 扫描实验，在红色 (644 nm) 和绿色 (514.5 nm) 激光束的连续照明下，对化学还原的标称纯 LiNbO3 晶体进行非线性吸收 (NLA) 的研究。测量的 NLA 大小与报道的在生长的 LiNbO3 中获得的 Z 扫描结果有很大不同。用红光获得的 NLA 的正值与吸收红光和近红外范围的小束缚极化子的产生有关。应用绿光导致光诱导透明，即 Z 扫描轨迹显示 NLA 的负号。 Z 扫描迹线的强度依赖性可以得出这样的结论：小 NbLi4+:NbNb4+ 双极子的光致解离和随后产生的小极化子对具有大双极子浓度的还原晶体中的非线性光学吸收做出了主要贡献。非线性吸收 (NLA) 通过开孔径 Z 扫描实验在红光连续照明下的化学还原名义纯 LiNbO3 晶体中进行了研究(644 nm) 和绿光 (514.5 nm) 激光束。测量的 NLA 大小与报道的在生长的 LiNbO3 中获得的 Z 扫描结果有很大不同。用红光获得的 NLA 的正值与吸收红光和近红外范围的小束缚极化子的产生有关。应用绿光导致光诱导透明，即 Z 扫描轨迹显示 NLA 的负号。 Z 扫描迹线的强度依赖性可以得出这样的结论：小 NbLi4+:NbNb4+ 双极子的光致解离以及随后产生的小极化子对具有大双极子浓度的还原晶体中的非线性光学吸收做出了主要贡献。
The nonlinear absorption (NLA) was studied by open-aperture Z-scan experiments in the chemically reduced nominally pure LiNbO3 crystals at cw-illumination with the red (644 nm) and green (514.5 nm) laser beams. The magnitude of the measured NLA is considerably different from the reported Z-scan results obtained in as-grown LiNbO3. The positive sign of NLA obtained with the red light has been related to the generation of the small bound polarons absorbing in red and near-IR ranges. Application of green light results in the light-induced transparency, i.e., the Z-scan traces show negative sign of NLA. Intensity dependence of Z-scan traces allows for conclusion that the photo-induced dissociation of small NbLi4+:NbNb4+ bipolarons and sequent generation of small polarons gives the dominating contribution to the nonlinear optical absorption in reduced crystals with a large bipolarons concentration.The nonlinear absorption (NLA) was studied by open-aperture Z-scan experiments in the chemically reduced nominally pure LiNbO3 crystals at cw-illumination with the red (644 nm) and green (514.5 nm) laser beams. The magnitude of the measured NLA is considerably different from the reported Z-scan results obtained in as-grown LiNbO3. The positive sign of NLA obtained with the red light has been related to the generation of the small bound polarons absorbing in red and near-IR ranges. Application of green light results in the light-induced transparency, i.e., the Z-scan traces show negative sign of NLA. Intensity dependence of Z-scan traces allows for conclusion that the photo-induced dissociation of small NbLi4+:NbNb4+ bipolarons and sequent generation of small polarons gives the dominating contribution to the nonlinear optical absorption in reduced crystals with a large bipolarons concentration.