Cross-sectional mapping of spectral absorbance features

• US 20060100490A1
• Filed: 10/04/2005
• Published: 05/11/2006
• Est. Priority Date: 10/05/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Tomophase Corporation
• Inventors: Li, Xiao-Li, Wang, Feiling, Norris, Peter E.
• Granted Patent: US 8,498,681 B2
• Time in Patent Office: Days
• US Class Current: 600/310
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/441 Skin evaluation, e.g. for skin disorder diagnosis
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/021 using plane or convex mirrors, parallel phase plates, or particular reflectors
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/027 Control of working procedures of a spectrometer; Failure detection; Bandwidth calculation
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/42 Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry beam switching arrangements G01J3/08
• CPC Class Codes: G01J 3/4338 Frequency modulated spectrometry
• CPC Class Codes: G01J 3/447 Polarisation spectrometry
• CPC Class Codes: G01J 3/453 by correlation of the amplitudes
• CPC Class Codes: G01N 21/39 using tunable lasers
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B

Abstract

Designs, implementations, and techniques for optically measuring a sample to obtain spectral absorbance map of the sample. Light at different wavelength bands may be used to detect different absorption features in the sample. Multiple light sources may be used including tunable lasers.

Claims

1. A method, comprising:

combining and guiding optical radiation from a plurality of light sources, each emitting at wavelengths within a spectral band different from others, towards a sample through a common optical waveguide;

reflecting a first portion of the combined radiation away from the sample at its vicinity while directing a second portion of the combined radiation to reach the sample;

collecting and guiding at least part of the reflected first portion and at least part of a reflected second portion from the sample towards a detection module through the common optical waveguide;

separating the light into a plurality of spectral bands corresponding to emitting spectral bands of the light sources; and

directing light radiation of the separated spectral bands to a plurality of light detectors, respectively.

2. The method as in claim 1, further comprising controlling the reflected first portion to propagate inside the common waveguide in a first propagation mode and the reflected second portion to propagate inside the common waveguide in a second propagation mode that is different from the first propagation mode.

3. The method as in claim 2, wherein the first propagation mode is a first polarization mode of the common waveguide and the second propagation mode is the second polarization mode that is perpendicular to the first polarization mode of the common waveguide.

4. The method as in claim 1, further comprising using broadband light emitters as the light sources, wherein each emitter has a broad spectrum centered at a wavelength different from wavelengths of other emitters.

5. The method as in claim 1, further comprising using tunable laser sources as the light sources, wherein each tunable laser source emits coherent light at a wavelength tunable through a spectral band that is different from spectral bands of other tunable laser sources.

6. The method as in claim 1, further comprising:

producing a delay between the reflected first and second portions; and

modulating the relative delay between the reflected first portion and the reflected second portion to measure a variation in power of light at each light detector.

7. The method as in claim 1, further comprising:

adjusting a relative delay between the reflected first portion and the reflected second portion received from the single waveguide at two different delay values to select a layer of material inside the sample to measure an optical absorption of the selected layer at each and every wavelength from the different light sources.

8. The method as in claim 1, further comprising simultaneously directing light from the different light sources through the single, common waveguide to the sample.

9. The method as in claim 1, further comprising sequentially directing light from the different light sources, one at a time, through the single, common waveguide to the sample.

10. A device for optically measuring a sample, comprising:

a plurality of light sources emitting light at different wavelength bands centered at different wavelengths;

a single waveguide to receive and guide the light at the different wavelength bands in a first propagation mode;

a probe head coupled to the waveguide to receive the light from the waveguide and to reflect a first portion of the light back to the waveguide in the first propagation mode and direct a second portion of the light to a sample, the probe head collecting reflection of the second portion from the sample and exporting to the waveguide the reflection as a reflected second portion in a second propagation mode different from the first propagation mode;

an optical differential delay unit to produce and control a relative delay between the reflected first portion and the reflected second portion received from the single waveguide in response to a control signal;

a detection module to receive the reflected first portion and the reflected second portion in the waveguide and to extract information of the sample carried by the reflected second portion; and

a control unit, which produces the control signal to the optical differential delay unit, to set the relative delay at two different bias values to select a layer of material inside the sample to measure an optical absorption of the selected layer at each and every wavelength from the different light sources.

11. The device as in claim 10, wherein the detection module comprises:

an optical device to separate light at different wavelength bands into different beams; and

a plurality of optical detectors to respectively receive and detector the different beams.

12. The device as in claim 10, wherein the detection module comprises:

an optical device to convert a part of received light in the first propagation mode and a part of received light in the second propagation mode into light in a third propagation mode that propagates along a first optical path and to convert remaining portions of the received light in the first and the second propagation modes into light in a fourth propagation mode that propagates along a second, different optical path;

a first optical element in the first optical path to separate light at different wavelength bands into a first set of different beams;

a plurality of first light detectors to respectively receive and detector the first set of different beams from the first optical element;

a second optical element in the second optical path to separate light at different wavelength bands into a second set of different beams; and

a plurality of second light detectors to respectively receive and detector the second set of different beams from the second optical element.

13. The device as in claim 11, wherein the first and second optical elements are optical gratings.

14. The device as in claim 10, wherein the detection module comprises a digital signal processor to process information of the sample in the reflected second portion and to generate spectral absorbance data of the sample.

15. The device as in claim 10, further comprising an optical element to receive the light at different wavelength bands from the light sources and to combine the received light into the single waveguide.

16. The device as in claim 10, wherein the light sources are fixed in their emitting wavelengths.

17. The device as in claim 10, further comprising a mechanism to move a position of the second portion of the light relative to the sample to measure different locations on the sample.

18. A device for optically measuring a sample, comprising:

a plurality of tunable laser sources emitting light within different wavelength bands centered at different wavelengths;

a single waveguide to receive and guide the light at the different wavelength bands in a first propagation mode;

a probe head coupled to the waveguide to receive the light from the waveguide and to reflect a first portion of the light back to the waveguide in the first propagation mode and direct a second portion of the light to a sample, the probe head collecting reflection of the second portion from the sample and exporting to the waveguide the reflection as a reflected second portion in a second propagation mode different from the first propagation mode;

a detection module to receive the reflected first portion and the reflected second portion in the waveguide and to extract information of the sample carried by the reflected second portion; and

a control unit to tune each tunable laser in a corresponding laser emitting wavelength band to obtain absorption measurements of the sample at different wavelengths within each corresponding wavelength band.

19. The device as in claim 18, wherein the detection module comprises:

an optical device to separate light at different wavelength bands into different beams; and

a plurality of optical detectors to respectively receive and detector the different beams.

20. The device as in claim 18, wherein the detection module comprises:

an optical device to convert a part of received light in the first propagation mode and a part of received light in the second propagation mode into light in a third propagation mode that propagates along a first optical path and to convert remaining portions of the received light in the first and the second propagation modes into light in a fourth propagation mode that propagates along a second, different optical path

a first optical element in the first optical path to separate light at different wavelength bands into a first set of different beams;

a plurality of first light detectors to respectively receive and detector the first set of different beams from the first optical element;

a second optical element in the second optical path to separate light at different wavelength bands into a second set of different beams; and

a plurality of second light detectors to respectively receive and detector the second set of different beams from the second optical element.