Tuned longitudinal surface plasmon resonance and third-order nonlinear optical properties of gold nanorods
Tuned longitudinal surface plasmon resonance and third-order nonlinear optical properties of gold nanorods
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DOI：
10.1088/0957-4484/22/27/275203
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发表时间：
2011-07
期刊：
影响因子：
3.5
通讯作者：
Yushi Tsutsui;T. Hayakawa;G. Kawamura;M. Nogami
中科院分区：
文献类型：
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作者：
Yushi Tsutsui;T. Hayakawa;G. Kawamura;M. Nogami
为了研究各向异性金属纳米粒子的三阶非线性光学性质与入射激光波长和表面等离子体共振（SPR）波长的关系，采用种子法制备了具有频率可调的纵向SPR模式的金纳米棒（GNRs），并分别加入十六烷基三甲基溴化铵（CTAB）和苄基二甲基氯化铵（BDAC）.采用近红外（800 nm）飞秒Z扫描和I扫描技术，研究了SPR波长分别为530 nm（球形）、800 nm（纳米棒）和1000 nm（纳米棒）的金溶胶（分别命名为530 GNSs、800 GNRs和1000 GNRs）的三阶非线性光学系数χ（3）的真实的实部和虚部.所有样品均表现出三阶非线性光学折射响应。然而，对于一个粒子的χ（3）的真实的部分，其等离子体激元峰被调谐到入射激光波长的800 GNR表现出比530 GNS强45倍的Reχ（3）值。更有趣的是，χ（3）的虚部在调谐的SPR波长处受到更大的影响。在这里，我们首先证明，800 GNRs显示等离子体增强的饱和吸收（SA）由于纵向SPR调谐到入射激光波长。
In order to elucidate the relationship for third-order nonlinear optical properties of anisotropic metal nanoparticles between the incident laser wavelength and surface plasmon resonance (SPR) wavelength, gold nanorods (GNRs) with a tuned longitudinal SPR mode in frequency were prepared by seed-mediated methods with two different surfactants, cetyltrimethylammonium bromide (CTAB) and benzyldimethylammonium chloride (BDAC). The real and imaginary parts of the third-order nonlinear optical susceptibilities χ(3) were examined by near-infrared (800 nm) femtosecond Z-scan and I-scan techniques for various gold sols with SPR wavelengths of 530 nm (spheres), 800 nm (nanorods) and 1000 nm (nanorods), named as 530GNSs, 800GNRs and 1000GNRs, respectively. All the samples showed intrinsically third-order nonlinear optical refractive responses. However, as for the real part of χ(3) for one particle, 800GNRs whose plasmon peak was tuned to the incident laser wavelength exhibited a Reχ(3) value 45 times stronger than 530GNSs. More interestingly, the imaginary part of χ(3) was more greatly influenced at the tuned SPR wavelength. Here we first demonstrate that 800GNRs showed plasmon-enhanced saturable absorption (SA) due to a longitudinal SPR tuned to the incident laser wavelength.