Compact raman or fluorescence excitation system

• US 20080084560A1
• Filed: 08/21/2007
• Published: 04/10/2008
• Est. Priority Date: 08/21/2006
• Status: Active Grant

• Current Assignee: Chemimage Corporation
• Original Assignee: Chemimage Corporation, Jingyun Zhang
• Inventors: Zhang, Jingyun
• Granted Patent: US 7,573,570 B2
• Time in Patent Office: Days
• US Class Current: 356/317
• 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 3/0256 Compact construction
• CPC Class Codes: G01J 3/0272 Handheld
• CPC Class Codes: G01J 3/44 Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
• CPC Class Codes: G01N 2201/0221 Portable; cableless; compact; hand-held

Abstract

A compact Raman and fluorescence spectroscopy system that uses a microprism or micromirror based optical structure to accomplish the introduction of excitation radiation with compactness and simplified system configuration for portable or mobile spectroscopy applications. A microprism may be glued to a surface location of a focusing lens in the system to directly receive the illumination signal without intervening optical components. Alternatively, the microprism may be simply placed in close physical proximity of the focusing lens without being glued thereto. On the other hand, a micromirror may be used instead of the microprism. The illuminating photons received by the microprism or micromirror may be directly transferred to the sample under investigation via the focusing lens. The compact system may be made portable and may further include an on-board spectrometer with or without a display unit. For chemical detecting applications, a detector (e.g., a CCD array) may also be provided along with the spectrometer.

Claims

1. A system comprising:

an illumination source for providing a plurality of illuminating photons in a first direction of propagation;

a microprism optically coupled to said illumination source to directly receive therefrom said plurality of illuminating photons in said first direction and to direct said received illuminating photons in a second direction of propagation; and

a focusing lens physically proximate to said microprism and optically coupled thereto, wherein said focusing lens is configured to directly receive said plurality of illuminating photons from said microprism in said second direction and to focus said illuminating photons onto a focusing location.

2. The system of claim 1, wherein said illumination source is selected from the group consisting of a laser, and a UV LED (Ultraviolet Light Emitting Diode).

3. The system of claim 1, wherein said illumination source is configured to provide said illuminating photons at a wavelength of 532 nm.

4. The system of claim 1, wherein said microprism is a right-angle (90°

) microprism.

5. The system of claim 4, wherein said focusing lens is configured to have a first surface and a second surface opposite to said first surface, wherein said first surface is physically closest to said right-angle microprism, and wherein said right-angle microprism is glued to a central location on said first surface of said focusing lens.

6. The system of claim 5, wherein a right-angle forming side of said right-angle microprism is glued to said central location on said first surface of said focusing lens.

7. The system of claim 5, wherein said second surface is physically closest to said focusing location.

8. The system of claim 4, wherein said focusing lens is configured to have a lens surface that is physically closest to said right-angle microprism, and wherein said right-angle microprism is placed in close proximity of an edge of said lens surface and within a numerical aperture of said focusing lens.

9. The system of claim 8, wherein said right-angle microprism is mechanically held in a stationary position in close proximity of said edge of said lens surface.

10. The system of claim 8, wherein a right-angle forming side of said right-angle microprism is glued to a substantially flat portion of said edge of said lens surface.

11. The system of claim 4, wherein said first direction of propagation and said second direction of propagation are substantially at right-angle to each other.

12. The system of claim 11, wherein said first direction of propagation is substantially vertical.

13. The system of claim 11, wherein said focusing lens is configured to receive said plurality of illuminating photons from said right-angle microprism in said second direction and to manipulate said illuminating photons from said second direction to a third direction of propagation so as to focus said illuminating photons onto said focusing location.

14. The system of claim 4, wherein said illumination source is configured to provide said illuminating photons in said first direction of propagation that is substantially parallel to a lens surface of said focusing lens that is physically closest to said right-angle microprism.

15. The system of claim 1, wherein said microprism is an equilateral microprism.

16. The system of claim 15, wherein said focusing lens is configured to have a lens surface that is physically closest to said equilateral microprism, and wherein said equilateral microprism is glued to a central location on said lens surface of said focusing lens.

17. The system of claim 16, wherein a non-triangular side of said equilateral microprism is glued to a substantially flat portion of said central location on said lens surface.

18. The system of claim 15, wherein an angle between said first direction of propagation and said second direction of propagation is other than a right angle.

19. The system of claim 15, wherein said illumination source is configured to provide said illuminating photons in said first direction of propagation that subtends an oblique angle with a lens surface of said focusing lens that is physically closest to said equilateral microprism.

20. The system of claim 1, further comprising:

a collection optics to collect photons scattered, reflected, or emitted from a sample when said sample is placed at said focusing location and illuminated by said plurality of illuminating photons from said focusing lens; and

a spectral analysis system coupled to said collection optics to receive a portion of said collected photons therefrom and to responsively measure a spectrum of said sample using said portion of said collected photons.

21. The system of claim 20, wherein said collection optics includes:

an optical filter for receiving photons emitted, scattered, or reflected from said sample and for generating filtered photons therefrom, wherein said filtered photons include those of the photons received from the sample that have wavelengths other than a wavelength of said illuminating photons; and

a collection lens coupled to said optical filter for sending said filtered photons received from the optical filter to the spectral analysis system.

22. The system of claim 20, wherein said spectral analysis system includes a dispersive spectrometer that comprises:

an entrance slit to receive said portion of said collected photons from said collection optics; and

a plurality of gratings to provide wavelength-specific dispersion of said portion of said collected photons received at the entrance slit so as to measure said spectrum of said sample.

23. The system of claim 20, further comprising:

a detector optically coupled to said spectral analysis system to receive an output signal therefrom and to responsively provide optical data to generate a wavelength-specific spectral image of said sample.

24. The system of claim 23, wherein the detector is one of the following:

a charged coupled device (CCD), and a complementary metal oxide semiconductor (CMOS) array.

25. The system of claim 24, further comprising:

a display unit coupled to said detector to display said wavelength-specific spectral image of said sample.

26. The system of claim 25, further comprising:

a programmable control unit, which, upon being programmed, is configured to control operations of one or more of the following;

said illumination source;

said focusing lens;

said collection optics;

said spectral analysis system;

said detector; and

said display unit.

27. The system of claim 1, further comprising:

an optical filter for receiving photons emitted, scattered, or reflected from said sample and for generating a first set of filtered photons therefrom, wherein said first set of filtered photons includes those of the photons received from the sample that have wavelengths other than a wavelength of said illuminating photons;

a liquid crystal-based tunable filter to receive said first set of filtered photons from said optical filter and to generate a second set of filtered photons therefrom, wherein said second set of filtered photons include only those photons from said first set of filtered photons that have a wavelength to which said tunable filter is tuned; and

a collection lens coupled to said tunable filter for sending said second set of filtered photons received from the tunable filter to a detector; and

said detector coupled to said collection lens to receive said second set of filtered photons therefrom and to responsively provide optical data to generate a wavelength-specific spectral image of said sample at the wavelength to which said tunable filter is tuned.

28. A system comprising:

an excitation source for providing a plurality of excitation photons in a first direction of propagation;

a micromirror optically coupled to said excitation source to directly receive therefrom said plurality of excitation photons in said first direction and to direct said received excitation photons in a second direction of propagation; and

a focusing lens physically proximate to said micromirror and optically coupled thereto, wherein said focusing lens is configured to directly receive said plurality of excitation photons from said micromirror in said second direction and to focus said excitation photons onto a focusing location.

29. The system of claim 28, wherein said excitation source is selected from the group consisting of a laser, and a UV LED (Ultraviolet Light Emitting Diode).

30. The system of claim 28, wherein said focusing lens is configured to have a lens surface that is physically closest to said micromirror, and wherein said micromirror is mechanically held in a stationary position in close proximity of a central location on said lens surface.

31. The system of claim 28, wherein said first direction of propagation and said second direction of propagation are substantially at right-angle to each other.

32. The system of claim 28, further comprising:

a collection optics to collect photons reflected, scattered, or emitted from a sample when said sample is placed at said focusing location and illuminated by said plurality of excitation photons from said focusing lens; and

a spectral analysis system coupled to said collection optics to receive a portion of said collected photons therefrom and to responsively measure a spectrum of said sample using said portion of said collected photons.

33. The system of claim 32, further comprising:

a detector optically coupled to said spectral analysis system to receive an output signal therefrom and to responsively provide optical data to generate a wavelength-specific spectral image of said sample; and

a display unit coupled to said detector to display said wavelength-specific spectral image of said sample.

34. A method comprising:

configuring an illumination source to provide a plurality of illuminating photons in a first direction of propagation;

changing direction of propagation of said plurality of illuminating photons from said first direction to a second direction of propagation using only a microprism or a micromirror; and

receiving said illuminating photons directly from said microprism or said micromirror in said second direction of propagation and focusing said illuminating photons onto a focusing location.

35. The method of claim 34, wherein said illumination source is configured to provide said illuminating photons at a wavelength selected from one of the following:

an NIR (near infrared) wavelength range, a visible wavelength range, and a UV (ultraviolet) wavelength range.

36. The method of claim 34, further comprising:

collecting photons reflected, scattered, or emitted from a sample when said sample is placed at said focusing location and illuminated by said plurality of illuminating photons focused onto said focusing location; and

measuring a spectrum of said sample using a portion of said collected photons.

37. The method of claim 36, further comprising:

generating optical data for a wavelength-specific spectral image of said sample using said portion of said collected photons; and

providing a display of said wavelength-specific spectral image of said sample.