Optical response measuring device and optical response measuring method

Patent metadata

Field	Value
Publication number	US-10345224-B2
Application number	US-201515517925-A
Country	US
Kind code	B2
Filing date	Oct 5, 2015
Priority date	Oct 8, 2014
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

An optical response measuring device is provided with a light source, first and second wavelength conversion elements and a light intensity sensor array. The light source generates a pair of light beams including light beams of first and second wavelengths, and the first wavelength conversion element generates measurement light. The measurement light is irradiated on an object for measurement and a detection light having first phase and second phase is obtained in response to this irradiation. A reference light that carries the phase of the pair of the pair light beams and the detection light both pass through a second wavelength conversion element to obtain a modulated reference light have first and second intensities. The first and second local intensities are then measured by the light intensity sensor array.

First claim

The invention claimed is:

1. An optical response measuring device comprising:
a light source for generating a pair of light beams, a first light beam of the pair of light beams having a first wavelength and the second light beam of the pair of light beams having a second wavelength;
a first wavelength conversion element on which the pair of light beams is made incident, first wavelength conversion element configured to generate a measurement light beam based on the first light beam and based on the second light beam;
a second wavelength conversion element, on which a detection light beam obtained from an illumination area on an object by the measurement light beam and a reference light beam are made incident, the second wavelength conversion element configured to generate a modulated reference light beam in response to both the reference light beam and the detection light beam, wherein the reference light beam has phases that are maintained relative to the phases of the pair of light beams, wherein the detection light beam includes at least two light beams, a first detection light beam having a first phase and being obtained at a first point of illumination of the object and a second detection light beam having a second phase and being obtained at a second point of illumination of the object, the first phase and the second phase containing responses of the object at the first point and the second point respectively, and wherein the second wavelength conversion element is configured to modulate the modulated reference light beam to have a first local intensity and a second local intensity in accordance with the first phase and the second phase of the at least two beams in the detection light beam respectively; and
a light intensity sensor array, on which the modulated reference light beams are made incident for measuring the first local intensity and the second local intensity in the modulated reference light beam, the first local intensity and the second local intensity corresponding respectively to the first phase and the second phase in the first and second light beams of the detection light beam.

2. The optical response measuring device according to claim 1 ,
wherein the detection light beam and the reference light beam are made incident on the second wavelength conversion element while being aligned with each other, and
wherein the modulated reference light beam is generated under a collinear phase matching condition.

3. The optical response measuring device according to claim 1 ,
wherein the light intensity sensor array is a two-dimensional sensor array,
wherein the illumination area on the object has a third point, the third point spanning a two-dimensional plane together with the first point and the second point,
wherein the detection light beam further includes a detection third light beam having a third phase and is obtained at the third point, the third phase containing a response of the object at the third point,
wherein the second wavelength conversion element is configured to modulate the modulated reference light beam to have a third local intensity in response to the third phase of the third detection light beam in the detection light beam,
wherein the light intensity sensor array is configured to measure the third local intensity of the modulated reference light beam together with the first and the second local intensities, and
wherein the optical response measuring device performs measurement over the object in the illumination area without conducting a scanning operation.

4. The optical response measuring device according to claim 1 , further comprising:
a modulation controller for modulating at least one of the first wavelength and the second wavelength.

5. A method of measuring an optical response comprising steps of:
generating a pair of light beams, a first light beam of the pair of light beams having of a first wavelength and a second light beam of the pair of light beams having a second wavelength;
obtaining a measurement light beam by making the pair of light beams incident on a first wavelength conversion element, the first wavelength conversion element configured to generate the measurement light beam based on the first light beam for illuminating an illumination area on the object;
obtaining a detection light beam having a first phase and a second phase by illuminating the illumination area with the measurement light beam, wherein the detection light beam includes at least two light beams, a first detection light beam having a first phase and being obtained at a first point under illumination and a second detection light beam having a second phase and being obtained at a second point under illumination, and the first phase and the second phase containing responses of the object at the first point and the second point, respectively;
obtaining a modulated reference light beam by making both a reference light beam and the detection light beam incident on a second wavelength conversion element, wherein the reference light beam has phases that are maintained with relative to the phases in the pair of light beams, and wherein the second wavelength conversion element is configured to modulate the modulated reference light beam to have a first local intensity and a second local intensity in accordance with the first phase and the second phase of the at least two beams in the detection light beam respectively; and
measuring the first local intensity and the second local intensity in the modulated reference light beam by making the modulated reference light beam incident on a light intensity sensor array, the first local intensity and the second local intensity corresponding respectively to the first phase and the second phase in the at least two light beams in the detection light beam.

6. The optical response measuring method according to claim 5 ,
wherein the detection light beam and the reference light beam is made incident on the second wavelength conversion element while being aligned with each other, and
wherein the modulated reference light beam is generated under a collinear phase matching condition.

7. The optical response measuring method according to claim 5 ,
wherein the light intensity sensor array is a two-dimensional sensor array,
wherein the illumination area on the object has a third point under illumination, the third point spanning a two-dimensional plane together with the first and the second points,
wherein the detection light beam further has a third detection light beam having a third phase and is obtained at the third point, the third phase containing response of the object at the third point,
wherein the second wavelength conversion element is configured to modulate the modulated reference light beam to have a third local intensity in response to the third phase of the third detection light beam in the detection light beam,
wherein the third local intensity of the modulated reference light beam is measured by the light intensity sensor array together with the first and the second local intensities, and
wherein the optical response measuring device performs measurement over the object in the illumination area without conducting a scanning operation.

8. The optical response measuring method according to claim 5 further comprising a step of:
modulating at least one of the first wavelength and the second wavelength.

Assignees

• Riken

Inventors

• Nawata Kouji
• Minamide Hiroaki
• Fan Shuzhen
• Qi Feng
• Ito Hiromasa

Classifications

• G01N21/3581

  using far infrared light; using Terahertz radiation · CPC title

• G01N21/17 Primary

  Systems in which incident light is modified in accordance with the properties of the material investigated (where the material investigated is optically excited causing a change in wavelength of the incident light G01N21/63) · CPC title

• G02F1/37

  for second-harmonic generation {(G02F1/3532 takes precedence)} · CPC title

• G02F1/365 Primary

  in an optical waveguide structure (G02F1/377, {G02F1/395} take precedence) · CPC title

• G01B9/02047

  using digital holographic imaging, e.g. lensless phase imaging without hologram in the reference path · CPC title