Pearce Kellie, Wang Fan, Reece Peter J
School of Physics, The University of New South Wales,Sydney, NSW, Australia.
Opt Express. 2011 Dec 5;19(25):25559-69. doi: 10.1364/OE.19.025559.
Applications of metallic nanoparticles are based on their strongly size-dependent optical properties. We present a method for combining optical tweezers with dark field microscopy that allows measurement of localised surface plasmon resonance (LSPR) spectra on single isolated nanoparticles without compromising the strength of the optical trap. Using this spectroscopic information in combination with measurements of trap stiffness and hydrodynamic drag, allows us to determine the dimensions of the trapped nanoparticles. A relationship is found between the measured diameters of the particles and the peak wavelengths of their spectra. Using this method we may also resolve complex spectra of particle aggregation and interactions within the tweezers.
金属纳米颗粒的应用基于其强烈的尺寸依赖性光学性质。我们提出了一种将光镊与暗场显微镜相结合的方法，该方法能够在不影响光阱强度的情况下，测量单个孤立纳米颗粒上的局域表面等离子体共振（LSPR）光谱。将这种光谱信息与光阱刚度和流体动力学阻力的测量结果相结合，使我们能够确定被捕获纳米颗粒的尺寸。我们发现颗粒的测量直径与其光谱的峰值波长之间存在一种关系。使用这种方法，我们还可以解析镊子内颗粒聚集和相互作用的复杂光谱。
