Optical measuring device and method, and nanoparticle measuring method and device

Abstract

The invention provides an optical measuring device capable of performing measuring using a transient diffraction grating by only adjusting probe light, and a nanoparticle measuring device using the same principle as the optical measuring device. An optical measuring device includes: a power supply; a containerthat stores a sample; a pair of electrodesandthat generate an electric force line distribution in which areas having high electric force line density and areas having low electric force line density are regularly arranged; a dielectrophoresis control unitthat controls the generation of a transient diffraction grating using dielectrophoresis of particles in the sample caused by applying the voltage to the pair of electrodesandand a variation in the transient diffraction grating due to the diffusion of the particles in the sample according to a variation in the applied voltage; a light sourceemitting light to the transient diffraction grating; and a plurality of photodetectorsdetecting diffracted light generated by the transient diffraction grating. In the optical measuring device, the particles are evaluated on the basis of a variation in the intensity of the diffracted light generated by the transient diffraction grating. Further, for example, the particle diameter of a nanoparticle is measured by the same principle as the optical measuring device uses. As a result, it is possible to increase the intensity of a signal and to improve the sensitivity and the S/N ratio, as compared to a dynamic scattering method.