Saturable and reverse saturable absorption in silver nanodots at 532 nm using picosecond laser pulses
Saturable and reverse saturable absorption in silver nanodots at 532 nm using picosecond laser pulses
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DOI：
10.1063/1.2990056
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发表时间：
2008-10-01
影响因子：
3.2
通讯作者：
Wokaun, Alexander
中科院分区：
文献类型：
--
作者：
Gurudas, Ullas;Brooks, Elijah;Wokaun, Alexander
在脉冲激光沉积法制备的银纳米点中观察到了532 nm处的饱和吸收（SA）和反饱和吸收（RSA）。用Z-扫描技术测量了这些薄膜的三阶非线性系数的真实的[Re chi（3））]和虚部[Im chi（3）]。在低输入辐照度下，焦点附近的吸收减少是由负的Im χ（（3））引起的，并产生SA。在较高的输入辐照度，RSA成为主导。从SA到RSA的转变表明，存在一个阈值辐照度，在该阈值辐照度处，涉及额外的非线性过程并成为主导。这些非线性过程的恢复时间是通过简并泵浦探测实验测量的。的影响被解释在激发态的电子动力学。(C)2008年美国物理学会。[DOI：10.1063/1.2990056]
Saturable absorption (SA) and reverse saturable absorption (RSA) at 532 nm were observed in Ag nanodots prepared by pulsed laser deposition. The real [Re chi((3))] and imaginary [Im chi((3))] parts of the third order nonlinearity of these films were measured using the Z-scan technique. At low input irradiances, the decrease in absorption near the focal point results from a negative Im chi((3)) and yields SA. At higher input irradiance, RSA becomes dominant. The transition from SA to RSA suggests that there is a threshold irradiance at which additional nonlinear process(es) is (are) involved and become dominant. The recovery time of these nonlinear processes was measured by a degenerate pump-probe experiment. The effects are explained in terms of the electron dynamics in the excited states. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.2990056]