Photoacoustic probe

Patent metadata

Field	Value
Publication number	US-9587976-B2
Application number	US-201213984736-A
Country	US
Kind code	B2
Filing date	Feb 17, 2012
Priority date	Feb 17, 2011
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

A photoacoustic transducer, such as a photoacoustic probe includes an optical fiber, diaphragm, at the optical fiber, whereby the optical fiber and diaphragm define a cavity, and an energy absorption film at the optical fiber, whereby an activating laser directed through the optical fiber can excite the energy absorption film to thereby generate an acoustic wave that, upon reflection upon a remote surface, can deflect the diaphragm and modify reflection of a detecting laser also directed through the optical fiber. A method of detecting an acoustic wave includes directing an activating laser through an optical fiber to an energy absorption film at the optical fiber, directing a detecting laser through the optical fiber and cavity to the diaphragm at the optical fiber, and measuring an interference pattern generated at least in part by reflection of the detecting laser from a surface of the diaphragm.

First claim

What is claimed is:

1. A photoacoustic probe, comprising
a) an optical fiber that defines a recess;
b) a diaphragm at the optical fiber, the diaphragm defining a surface, whereby at least a portion of the recess and at least a portion of the surface of the diaphragm define a cavity; and
c) an energy absorption film at the optical fiber,
whereby an activating laser directed through the optical fiber can excite the energy absorption film to thereby generate an acoustic wave that, upon reflection from a remote surface, can deflect the diaphragm and modify reflection of a detecting laser also directed through the optical fiber.

2. The photoacoustic probe of claim 1 , wherein the optical fiber defines a first planar surface.

3. The photoacoustic probe of claim 2 , wherein the energy absorption film is at the first planar surface.

4. The photoacoustic probe of claim 3 , wherein the diaphragm is within the recess.

5. The photoacoustic probe of claim 4 , wherein the diaphragm is recessed within the recess from the first surface.

6. The photoacoustic probe of claim 2 , wherein the optical fiber includes a second surface that is raised from the first surface and is essentially parallel to the first surface.

7. The photoacoustic probe of claim 6 , wherein the recess is further defined by an edge of the second surface and the diaphragm is at the second surface.

8. The photoacoustic probe of claim 7 , wherein the energy absorbing film is peripheral to the raised second surface when viewed orthogonally to the plane of the second surface.

9. The photoacoustic probe of claim 2 , wherein the diaphragm is at the first planar surface.

10. The photoacoustic probe of claim 9 , wherein the energy absorption film is at the diaphragm.

11. The photoacoustic probe of claim 10 , wherein the energy absorption film is peripheral to the portion of the diaphragm that, in combination with the optical fiber, defines the cavity.

12. The photoacoustic probe of claim 11 , wherein the optical fiber and the diaphragm together define a trench that at least partially partitions the energy absorption film from the portion of the diaphragm that, in combination with the optical fiber, defines the cavity.

13. The photoacoustic probe of claim 1 , wherein the probe includes a plurality of energy absorption films.

14. The photoacoustic probe of claim 13 , wherein at least a portion of the energy absorption films are in the same plane.

15. The photoacoustic probe of claim 14 , wherein the energy absorption films are at least partially partitioned by a trench defined at least in part by the optical fiber.

16. The photoacoustic probe of claim 15 , wherein the trench is further defined by the diaphragm.

17. The photoacoustic probe of claim 1 , wherein the energy absorption film includes gold.

18. The photoacoustic probe of claim 17 , wherein the energy absorption film further includes at least one of silver, polydimethylsiloxane (PDMS), anodized aluminum oxide (AAO), anodized tin oxide (ATO), and epoxy.

19. The photoacoustic probe of claim 17 , wherein at least a portion of the gold is in the form of at least one of nanoparticles, nanostructures and nanocomposites.

20. The photoacoustic probe of claim 19 , wherein the nanoparticles are in the form of nanorods.

21. The photoacoustic probe of claim 20 , wherein the nanorods have an aspect ratio in a range of from about 1.0 to about 6.5 and an effective radius in a range of from about 8 nm to about 25 nm.

22. The photoacoustic probe of claim 21 , wherein at least a portion of the gold is in the form of nanoparticles.

23. The photoacoustic probe of claim 22 , wherein the nanoparticles are in the form of nanospheres.

24. The photoacoustic probe of claim 23 , wherein the nanospheres have an average diameter in a range of from about 10 nm to about 100 nm.

25. The photoacoustic probe of claim 22 , wherein the nanoparticles are in the form of nanoshells.

26. The photoacoustic probe of claim 25 , wherein the nanoshells have a total radius in the range from about 50 nm to about 150 nm and a core/shell ratio in a range of from about 0.1 to about 1.

27. The photoacoustic probe of claim 1 , wherein the optical fiber is a multimode optical fiber and the probe further includes a single-mode fiber connected to the multimode optical fiber.

28. The photoacoustic probe of claim 1 , further including tubing at the optical fiber, and whereby the tubing, the optical fiber and the diaphragm define the cavity.

29. A method of detecting an acoustic wave, comprising the steps of:
a) directing an activating laser through an optical fiber to an energy absorption film at the optical fiber to thereby generate an acoustic wave;
b) directing a detecting laser through the optical fiber and a cavity to a diaphragm at the optical fiber, the cavity being defined by the optical fiber and the diaphragm; and
c) measuring an interference pattern generated at least in part by a reflection of the detecting laser from a surface of the diaphragm,
wherein the interference pattern is indicative of the reflection of the acoustic wave from a remote surface.

30. The method of claim 29 , further including the step of inserting the optical fiber into a chamber or lumen.

31. The method of claim 30 , wherein the chamber or lumen is inside of a mammalian body.

32. The method of claim 31 , wherein the detecting laser includes a tunable diode laser.

33. The method of claim 29 , wherein the activating laser is actuated separately in time from measurement of the interference pattern generated by the detecting laser.

34. The method of claim 29 , further comprising the step of multiplexing the activating laser and the detecting laser.

35. The method of claim 34 , wherein the multiplexing occurs according to a time division multiplexing (TDM) scheme.

36. The method of claim 29 , wherein the activating laser includes at least two activating lasers of different wavelengths and wherein the energy absorption layer includes at least two energy absorption films, each activating laser activating a different energy absorption film at the optical fiber.

37. The method of claim 36 , wherein the wavelengths of the activating lasers are in a range of from about 500 nm to about 1200 nm.

38. The method of claim 37 , wherein the wavelength of one of the activating lasers is 527 nm and the wavelength of a second activating laser is 1064 nm.

39. The method of claim 36 , wherein the activating lasers are pulsed lasers.

40. The method of claim 36 , wherein the energy absorption films have different optical absorption peaks that correspond to the different optical wavelengths of the activating lasers.

41. The method of claim 40 , wherein the energy absorption films are arranged in an array at the optical fiber and the activating lasers independently excite corresponding energy absorption films to form an acoustic wave interference pattern and thereby direct the generated acoustic wave.

42. A photoacoustic probe system, comprising
a) a photoacoustic probe, including
i) an optical fiber that defines a recess,
ii) a diaphragm at the optical fiber, the

Assignees

• Wang Xingwei Vivian
• Wu Nan
• Univ Massachusetts

Inventors

• Wang Xingwei Vivian
• Wu Nan

Classifications

• G01N29/2418 Primary

  using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics (photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046) · CPC title

• A61B2562/12

  Manufacturing methods specially adapted for producing sensors for in-vivo measurements · CPC title

• G01H9/004 Primary

  using fibre optic sensors (light guides per se G02B6/00, acousto-optical devices specially adapted for gating or modulating in optical wave guides G02F1/125) · CPC title

• A61B5/0095

  by applying light and detecting acoustic waves, i.e. photoacoustic measurements · CPC title

• A61B5/0084

  for introduction into the body, e.g. by catheters (A61B5/1459 takes precedence) · CPC title