High-Resolution Nanoparticle Size Measurement Based on Scattering Efficiency Factor Difference Ratio under Three-Wavelength Excitation

This study focuses on the light scattering spectral properties of spherical nanoparticles under multilaser excitation and proposes the concept of scattering efficiency factor difference ratio (SEFDR) for high-resolution nanoparticle size measurement. The effects of excitation wavelength, particle size, and scattering angle on the scattering spectra are investigated and simulated. Based on the simulation, the SEFDRs for particles of different sizes under different combinations of excitation wavelengths are simulated. The SEFDR calculation can effectively eliminate noise to achieve high-resolution measurements. In experiments, three lasers with center wavelengths of 380, 785, and 1064 nm are used as excitation light sources to measure particle diameter between 33 and 147 nm; the minimum measurable particle diameter is 33 nm. Using three excitation light sources with center wavelengths between 210 and 628 nm, the minimum measurable particle diameter can be broadened to 20 nm. When the spectrometer signal-to-noise ratio is 1000:1, the resolution of particles with a diameter of 33 nm can reach 0.05 nm under ideal conditions. © 1963-2012 IEEE.