Integrated miniaturized fiber optic probe
A fiber optic probe having one or more photodetectors bound thereto is provided. By directly integrating thin, flexible photodetectors with an optical fiber, the probes provide a compact structure that increases throughput and decreases cost, making it practical for a clinical use. In some embodiments, the fiber optic probes are small enough for insertion into the shaft of a needle, such as a biopsy needle.
1. An apparatus comprising:
(a) light source;
(b) an optical fiber having a distal end, a proximal end and a side-wall, the proximal end in optical communication with the light source, wherein the optical fiber is configured to emit light from its distal end, at least one location along its side-wall, or both;
(c) at least one photodetector having a device layer bonded to and conforming to the curvature of the curved outer surface of the side-wall of the optical fiber, wherein the at least one photodetector is positioned such that light from the optical fiber will not directly impinge upon the at least one photodetector; and
(d) an electrically conductive lead in electrical communication with at least one photodetector.
2. An apparatus comprising:
(a) an optical fiber;
(b) at least one photodetector having a device layer bonded to and conforming to the curvature of the curved outer surface of the side-wall of the optical fiber;
(c) an electrically conductive lead in electrical communication with at least one photodetector; and
(d) a layer of electrically conductive material disposed between the optical fiber and at least one photodetector, wherein the layer of electrically conductive material provides a back electrode for the at least one photodetector.
3. The apparatus of claim 1 , further comprising a layer of dielectric material coating a portion of the photodetector.
4. The apparatus of claim 1 , wherein the at least one photodetector is located no more than 10 mm from the distal end of the optical fiber.
5. The apparatus of claim 1 , wherein the optical fiber is configured to emit light from its distal end and from at least one additional location along its side-wall, the apparatus further comprising at least one additional photodetector having a device layer bonded to and conforming to the curvature of the curved outer surface of the side-wall of the optical fiber in the vicinity of the at least one additional light-emitting location.
6. The apparatus of claim 1 , comprising a plurality of photodetectors disposed around the circumference of the optical fiber, wherein each of the plurality of photodetectors is bonded to and conforms to the curvature of the curved outer surface of the side-wall of the optical fiber.
7. The apparatus of claim 6 , wherein the optical fiber is configured to emit light at a plurality of locations around its circumference, and further wherein at least one of the plurality of photodetectors is located in the vicinity of each of the plurality of light-emitting locations.
8. The apparatus of claim 1 , further comprising a biopsy needle containing the optical fiber.
9. A method for using the apparatus of claim 1 , the method comprising:
(a) placing the optical fiber in close proximity to a sample; and
(b) emitting light from the optical fiber;
wherein return light from the sample is detected by the at least one photodetector via absorption of said return light by the photodetector.
10. The method of claim 9 , wherein the sample comprises a biologic tissue.
11. The method of claim 10 , wherein the optical fiber is contained in a biopsy needle and placing the optical fiber in close proximity to the sample comprises inserting the biopsy needle into the biological tissue.
12. The method of claim 10 , further comprising using the detected return light to measure the wavelength-dependent absorbance characteristics of hemoglobin in the biological tissue sample.
13. The method of claim 9 , wherein the return light is absorbed by the at least one photodetector in vivo.
14. The method of claim 9 , wherein the return light is light scattered from the sample.
15. The method of claim 9 , wherein the sample comprises a chromophore and the return light is florescence emitted from the sample.
16. The apparatus of claim 1 , wherein the radius of curvature of the device layer bonded to and conforming to the curvature of the curved outer surface of the side-wall of the optical fiber is greater than the thickness of the device layer.
17. The apparatus of claim 1 , wherein the at least one photodetector is located no more than 2 mm from the distal end of the optical fiber.
18. The apparatus of claim 16 , wherein the at least one photodetector comprises device layers having a thickness of no greater than about 10 μm.
19. The apparatus of claim 18 , wherein the at least one photodetector is a thin film semiconductor photodetector having direct-bandgap semiconductor-based device layers.
20. The apparatus of claim 2 , wherein the at least one photodetector is further positioned such that reflected or fluorescent return light from the sample in close proximity to the optical fiber will be detected by the photodetector via absorption of said return light by the photodetector.