US 2010/0149532 A1 · METHOD AND APPARATUS FOR OPTICAL MEASUREMENT

Abstract

In the case of generating a diffraction grating resulting from the density distribution of particles by applying a spatially periodic electric field to a sample having particles dispersed movably in a medium, measuring diffracted light obtained by exposing the diffraction grating to a parallel light flux, and calculating the diffusion coefficient and/or size of the particles from the temporal change in the intensity of the diffracted light, the diffraction grating is exposed to multiple types of parallel light fluxes having mutually different wavelengths simultaneously or sequentially, the diffracted light is measured separately for each wavelength, and the measurement results are used selectively for calculation of the diffusion coefficient and/or size of the particles, and whereby the measurement can be carried out accurately without being affected by a plasmon resonance phenomenon even for metal particles.

Claims19

Dependent claims

A method for optical measurement comprising:

applying a spatially periodic electric field to a sample having particles dispersed movably in a medium to cause a attracting force to operate on the particles;
generating a diffraction grating resulting from the density distribution of the particles in the medium;
detecting the varying intensity of diffracted light generated by exposing the diffraction grating to a collimated light flux;
and evaluating the characteristics of the particles and/or medium based on the temporal change in the intensity of diffracted light in the process of generation or extinction of the diffraction grating through the application of the electric field or the stopping or modulation of the application, wherein
the diffraction grating resulting from the density distribution of the particles is illuminated to multiple collimated light fluxes having mutually different wavelengths for the same sample, the varying intensity of diffracted light is detected separately for each of the collimated light fluxes of the respective wavelengths, and the detection results are used selectively to evaluate the characteristics of the particles and/or medium.

2 more elements

An apparatus for optical measurement comprising:

a cuvette for storing therein a sample having particles dispersed movably in a medium;
a power source for generating an AC or DC voltage;
an electrode pair adapted to generate a spatially periodic electric field in the cuvette through the application of the voltage from the power source;
an irradiation optical system for irradiating a collimated light flux to a diffraction grating resulting from the density distribution of the particles generated in the cuvette through the application of the voltage;
a detection optical system for detecting diffracted light generated by the collimated light flux transmitting through the diffraction grating;
voltage control means for applying the voltage from the power source to the electrode pair and stopping or modulating the application of the voltage to generate and extinction the diffraction grating resulting from the density distribution of the particles in the cuvette;
and data processing means for retrieving outputs from the detection optical system to evaluate the characteristics of the particles and/or medium, wherein
the irradiation optical system is adapted to selectively radiate multiple collimated light fluxes having mutually different wavelength ranges and the data processing means is adapted to retrieve detection outputs of diffracted light from the diffraction grating by the collimated light fluxes of the respective wavelength ranges.

5 more elements

An apparatus for optical measurement comprising:

a cuvette for storing therein a sample having particles dispersed movably in a medium;
a power source for generating an AC or DC voltage;
an electrode pair adapted to generate a spatially periodic electric field in the vessel through the application of the voltage from the power source;
an irradiation optical system for irradiating a collimated light flux to a diffraction grating resulting from the density distribution of the particles generated in the cuvette through the application of the voltage;
a detection optical system for detecting diffracted light generated by the collimated light flux transmitting through the diffraction grating;
voltage control means for applying the voltage from the power source to the electrode pair and stopping or modulating the application of the voltage to generate and extinct the diffraction grating resulting from the density distribution of the particles in the cuvette;
and data processing means for retrieving outputs from the detection optical system to evaluate the characteristics of the particles and/or medium, wherein
the irradiation optical system is adapted to simultaneously radiate multiple collimated light fluxes having mutually different wavelength ranges, the detection optical system is adapted to simultaneously and separately detect diffracted light appearing at different angles when the collimated light fluxes transmit through the diffraction grating, and the data processing means is adapted to retrieve detection outputs of the diffracted light by the detection optical system.

5 more elements

Dependencies are inferred from the claim text.

Method and apparatus for optical measurement

Life of this patent

Method and apparatus for optical measurement

Life of this patent

Abstract

Claims19