Detection of single gold nanoparticles using spatial modulation spectroscopy implemented with a galvo-scanning mirror system.
The optical extinction of single nanoparticles can be sensitively detected by spatial modulation spectroscopy (SMS), where the particle is moved in and out of a tightly focused laser beam with a piezo-device. Here we show that high sensitivity can be obtained by modulating the beam with a galvo-mirror system, rather than by moving the sample. This work demonstrates an inexpensive method for making a SMS microscope, and shows how an existing laser scanning microscope can be adapted for SMS measurements. The galvo-mirror technique also allows SMS measurements to be performed in a liquid, which is difficult to do with piezo-modulation.
Mary Sajini
MS
Devadas
Zhongming
Z
Li
Todd A
TA
Major
Shun Shang
SS
Lo
Nicolas
N
Havard
Kuai
K
Yu
Paul
P
Johns
Gregory V
GV
Hartland