Open AccessQuick and easy measurement of particle size of Brownian particles and plankton in water using a self-mixing laser
Author(s) -
Seiichi Sudol,
Yoshihiko Miyasaka,
Kenju Otsuka,
Yohei Takahashi,
Tomohiko Oishi,
JingYuan Ko
Publication year - 2006
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.14.001044
Subject(s) - laser , optics , materials science , particle size , mixing (physics) , brownian motion , seawater , particle (ecology) , mie scattering , laser power scaling , light scattering , physics , scattering , chemistry , oceanography , quantum mechanics , geology
We describe a method for quickly and easily measuring the size of small particles in suspensions. This method uses a self-mixing laser Doppler measurement with a laser-diode-pumped, thin-slice LiNdP(4)O(12) laser with extremely high optical sensitivity. The average size of the particles in Brownian motion is determined by a Lorentz fitting of the measured power spectrum of the modulated self-mixing laser light resulting from the motion. The dependence of the measured power spectra on particle size and concentration was quantitatively identified from the results of a systematic investigation of small polystyrene latex particles with different diameters and concentrations. The sizes and ratios of particles with different diameters mixed in water were accurately measured. An application of this self-mixing laser method for estimation of the average size of plankton in seawater showed that it is a practical method for characterizing biological species.