NSF Center for Biophotonics Science and Technology, University of California, Davis, Sacramento, CA 95817, USA.
Chemphyschem. 2013 Jun 24;14(9):1951-5. doi: 10.1002/cphc.201300091. Epub 2013 May 6.
We used coherent anti-Stokes scattering (CAS) to characterize individual gold nanorods (GNRs) and GNR aggregates. By creating samples with different densities of GNRs on silicon wafer substrates, we were able to determine surface coverage by scanning electron microscopy (SEM) and then correlate the coverage to the CAS intensities of the samples. The observed CAS signal intensity was quadratically dependent on the number of particles. We also examined the CAS signal as a function of the excitation polarization and found that the strongest signals in regularly oriented GNRs were observed when the beam polarization was aligned with the longitudinal axis of the GNRs. Irregularly oriented GNRs exhibited a different scattering pattern to that observed for regularly oriented GNRs. The polarization-dependent scattering from oriented GNRs showed cos(6)(θ) behavior. By imaging nanoscale-sized GNR patterns using CAS and evaluating the results with SEM, we show that CAS can be used for efficient, label-free imaging of nanoscale metallic particles.
我们使用相干反斯托克斯散射（CAS）来描述单个金纳米棒（GNR）和 GNR 聚集体。通过在硅片衬底上创建具有不同 GNR 密度的样品，我们能够通过扫描电子显微镜（SEM）确定表面覆盖率，然后将覆盖率与样品的 CAS 强度相关联。观察到的 CAS 信号强度与粒子数的平方成正比。我们还研究了 CAS 信号作为激发偏振的函数，并发现当光束偏振与 GNR 的纵轴对齐时，在规则取向的 GNR 中观察到最强的信号。不规则取向的 GNR 表现出与规则取向的 GNR 观察到的不同散射模式。取向 GNR 的偏振相关散射表现出 cos(6)(θ)行为。通过使用 CAS 对纳米尺度的 GNR 图案进行成像，并使用 SEM 评估结果，我们表明 CAS 可用于高效、无标记的纳米级金属粒子成像。
