Spectroscopy of single metallic nanoparticles using total internal reflection microscopy

Abstract

We have developed a simple, fast, and flexible technique to measure optical scattering spectra of individual metallic nanoparticles. The particles are placed in an evanescent field produced by total internal reflection of light from a halogen lamp in a glass prism. The light scattered by individual particles is collected using a conventional microscope and is spectrally analyzed by a nitrogen-cooled charge-coupled-device array coupled to a spectrometer. This technique is employed to measure the effect of particle diameter on the dephasing time of the particle plasmon resonance in gold nanoparticles. We also demonstrate the use of this technique for measurements in liquids, which is important for the potential application of particle plasmons in chemical or biological nanosensors

Ultrafast resonant optical scattering from single gold nanorods: Large nonlinearities and plasmon saturation

“…21,22,26 Incident light is focussed onto the sample through a glass prism. Scattered light is collected using a microscope objective and is imaged onto a multimode optical fiber, which selects a 1.5 µm spot on the sample for observation.…”

Optical Properties and Ultrafast Dynamics of Metallic Nanocrystals

“…With the simple setup of an optical microscope the homogeneous linewidth was measured for gold nanodots and nanorods by Soennichsen et al (58,65). They found much longer dephasing times for gold nanorods of up to 18 fs determined from the homogeneous width of the longitudinal surface plasmon resonance compared to 1-5 fs for nanodots, and they explained their results with a reduced interband damping in the nanorods because of a decreased spectral overlap between the longitudinal plasmon resonance at lower energies and the interband transition.…”

The Optimal Aspect Ratio of Gold Nanorods for Plasmonic Bio-sensing

“…Here, the nanoparticle sensor acts in a way similar to sensors exploiting the surface plasmon resonance on gold films, which is a standard method in many laboratories. However, whereas the detection scheme for surface plasmon resonance is usually a shift in the plasmon excitation angle [12], plasmonic nanoparticles show a shift in the plasmon resonance frequency [13]. The main advantage of using nanoscopic particles as sensors instead of metal films is their extremely small size which allows one, in principle, to measure analytes in volumes as small as attoliters [14].…”