Interferometric apparatus and method for detection and characterization of particles using light scattered therefrom

Claim 2

Apparatus for the indentification and characterization of particles in a sample by observing light scattered therefrom, comprising in combination: means for producing a first radiation having a first wavelength and a first polarization; means for producing a second radiation substantially collinear with said first radiation and having a second wavelength and a second polarization substantially orthogonal to said first polarization; containment means containing said sample, for allowing said first and second radiations to scatter from collisions with said particles in said sample; polarization means receiving scattered first and second radiations for resolving said scattered first and second radiations, said polarization means having an axis of transmission along which resolved scattered first and second radiations pass; photodetector means receiving and detecting said resolved scattered first and second radiations for outputting a beat frequency resulting from interaction between said resolved scattered first and second radiations, said beat frequency having a relative phase and amplitude; and measurement means receiving said beat frequency for measuring and outputting said relative phase of said beat frequency, for use in identifying and characterizing said particles.

Claim 3

The apparatus as described in claim 1, further comprising measurement means for measuring and outputting said amplitude of said beat frequency, for use in identifying and characterizing said particles.

Claim 4

The apparatus as described in claim 2, further comprising means for moving a combination of said polarization means and said photodetector means about said containment means to measure and output said relative phase and said amplitude of said beat frequency as functions of scattering angle.

Claim 5

The apparatus as described in claim 1, further comprising means located intermediate said containment means and said photodetector means for defining the volume of said scattered first and second radiations.

Claim 6

The apparatus as described in claim 1, wherein said first polarization and said second polarization comprise linear polarizations.

Claim 7

The apparatus as descried in claim 5, wherein the angle of said axis of transmission of said polarization means with respect to the axis of said first polarization is selected from the group comprising 0°, 45°, and 90°.

Claim 8

The apparatus as described in claim 1, wherein said means for producing a first radiation and said means for producing a second radiation comprise laser means.

Claim 9

The apparatus as described in claim 7, wherein said first and second radiations have a difference frequency of not more than 100 MHz.

Claim 10

The apparatus as described in claim 8, wherein said difference frequency is stable to at least 0.1 parts per million.

Claim 11

The apparatus as described in claim 7, wherein said laser means comprises a two-frequency Zeeman effect laser.

Claim 12

The apparatus as described in claim 1, wherein said first polarization and said second polarization comprise circular polarizations.

Claim 13

The apparatus as described in claim 11, wherein said polarization means includes a circular polarizer.

Claim 16

The method as described in claim 13, further comprising the steps of measuring and outputting said amplitude of said beat frequency.

Claim 17

The method as described in claim 14, further comprising the steps of measuring said relative phase and said amplitude of said beat frequency at a plurality of scattering angles, and outputting said relative phase and said amplitude of said beat frequency as functions of said plurality of scattering angles.

Claim 18

The method as described in claim 13, further comprising the step of defining the volume of said scattering first and second radiations after the step of scattering said first and second radiations, and again after the step of outputting resolved scattered first and second radiations.

Claim 19

The method as described in claim 13, wherein said first and second radiations comprise laser radiations.

Claim 20

The method as described in claim 17, wherein the difference frequency between said first wavelength and said second wavelength is not more than 100 MHz.

Claim 21

The method as described in claim 18, wherein said difference frequency is stable to at least 0.1 parts per million.

Claim 22

The method as described in claim 17, wherein said laser radiations comprise two-frequency Zeeman effect laser radiations.

Claim 23

The method as described in claim 13, wherein said first polarization and said second polarization comprise linear polarizations.

Claim 24

The method as described in claim 21, wherein said predetermined polarization angle with respect to the axis of said first polarization is from the group comprising 0°, 45°, and 90°.

Claim 25

The method as described in claim 13, wherein said first polarization and said second polarization comprise circular polarizations;

Claim 26

The method as described in claim 23, wherein said step of receiving and resolving said scattered first and second radiations includes resolving said scattered first and second radiation into circularly polarized scattered first and second radiations.

Claim 27

Apparatus for the indentification and characterization of individual particles in a flow by observing light scattered therefrom, comprising in combination; means for producing a first radiation having a first wavelength and a first polarization; means for producing a second radiation substantially collinear with said first radiation and having a second wavelength and a second polarization substantially orthogonal to said first polarization; containment means controlling the flow of said individual particles for allowing said first and second wavelengths to scatter from collisions with said individual particles; polarization means receiving scattered first and second radiations for resolving said scattered first and second radiations, said polarization means having an axis of transmission along which resolved scattered first and second radiations pass; photodetector means receiving and detecting said resolved scattered first and second radiations for outputting the beat frequency resulting from the interaction between said resolved scattered first and second radiations, said beat frequency having a relative phase and amplitude; and measurement means receiving said beat frequency for measuring and outputting said relative phase as a function of time for use in identifying and characterizing said individual particles.

Claim 28

Apparatus for the indentification and characterization of individual particles in a flow by observing light scattered therefrom, comprising in combination; means for producing a first radiation having a first wavelength and a first polarization; means for producing a second radiation substantially collinear with said first radiation and having a second wavelength and a second polarization substantially orthogonal to said first polarization; containment means controlling the flow of said individual particles for allowing said first and second wavelengths to scatter from collisions with said individual particles; polarization means receiving scattered first and second radiations for resolving said scattered first and second radiations, said polarization means having an axis of transmission along which resolved scattered first and second radiations pass; photodetector means receiving and detecting said resolved scattered first and second radiations for outputting the beat frequency resulting from the interaction between said resolved scattered first and second radiations, said beat frequency having a relative phase and amplitude; and measurement means receiving said beat frequency for measuring and outputting said relative phase as a function of time for use in identifying and characterizing said individual particles.

Claim 29

The apparatus as described in claim 25, further comprising means for measuring and outputting said amplitude of said beat frequency as a function of time for use in identifying and characterizing said individual particles.

Claim 30

The apparatus as described in claim 26, further comprising means for measuring and outputting said relative phase and said amplitude of said beat frequency as functions of time at a plurality of scattering angles.

Claim 31

The apparatus as described in claim 25, wherein said means for producing said first and second radiations comprise laser means.

Claim 32

The apparatus as described in claim 24, wherein said first and second radiations have a difference frequency of no more than 100 MHz.

Claim 33

The apparatus as described in claim 29, wherein said difference frequency is stable to at least 0.1 parts per million.

Claim 34

The apparatus as described in claim 28, wherein said laser means comprises a two-frequency Zeeman effect laser.

Claim 35

The apparatus as described in claim 25, wherein said first polarization and said second polarization comprise linear polarizations.

Claim 36

The apparatus as described in claim 32, wherein the angle of said axis of transmission of said polarization means with respect to the axis of said first polarization is selected from the group comprising 0°, 45°, and 90°.

Claim 37

The apparatus as described in claim 25, wherein said first polarization and said second polarization comprise circular polarizations.

Claim 38

The apparatus as described in claim 34, wherein said polarization means comprises a circular polarizer.

Claim 39

The apparatus as described in claim 25, further comprising focusing means for reducing the diameter of said first and second radiations prior to collision with said individual particles.

Claim 40

The apparatus as described in claim 25, further comprising light gathering means intermediate of said containment means and said polarization means for maximizing collection of said scattered first and second radiations.

Claim 41

The apparatus as described in claim 25, further comprising slit means intermediate of said containment means and said polarization means, for improving spatial resolution of said scattered first and second radiations.

Claim 44

The method as described in claim 39, further comprising the steps of measuring and outputting said amplitude of said beat frequency as a function of time for use in identifying and characterizing said individual particles.

Claim 45

The method as described in claim 40, further comprising the step of measuring said relative phase and said amplitude as functions of time at a plurality of scattering angles, and outputting said relative phase and said amplitude as functions of time and of said scattering angles.

Claim 46

The method as described in claim 39, wherein said first polarization and said second polarization comprise linear polarizations.

Claim 47

The method as described in claim 42, wherein said predetermined polarization angle with respect to the axis of said first polarization is chosen from the group comprising 0°, 45°, and 90°.

Claim 48

The method as described in claim 39, wherein said first and second radiations comprise laser radiations.

Claim 49

The method as described in claim 44, wherein the difference frequency between said first wavelength and said second wavelength is not more than 100 MHz.

Claim 50

The method as described in claim 45, wherein said difference frequency is stable to at least 0.1 parts per million.

Claim 51

The method as described in claim 44, wherein said laser radiations comprise two-frequency Zeeman effect laser radiations.

Claim 52

The method as described in claim 39, wherein said first polarization and said second polarization comprise circular polarizations.

Claim 53

The method as described in claim 48, wherein said step of receiving and resolving said scattered first and second radiations further comprises resolving said scattered first and second radiations into circularly polarized scattered first and second radiations.

Claim 54

The method as described in claim 39, further comprising the step of reducing the beam diameter of said first and second radiations before being scattered by said particles in a flow.

Claim 55

The method as described in claim 39, further comprising the step of optically collecting said scattered first and second radiations before said step of receiving and resolving said scattered first and second radiations.