Apparatus and method for irradiating a scattering medium

• US 8,817,255 B2
• Filed: 12/15/2011
• Issued: 08/26/2014
• Est. Priority Date: 12/17/2010
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Masumura, Takahiro
• Primary Examiner(s): Lyons, Michael A
• Application Number:
  US13/327,627
• Publication Number:
  US 20120182558A1
• Time in Patent Office: 985 Days
• Field of Search: 356/337, 356/338, 356/432, 356/436, 356/441
• US Class Current: 356/338
• CPC Class Codes: A61B 5/0068 Confocal scanning
• CPC Class Codes: A61B 5/0073 by tomography, i.e. reconstruction of 3D images from 2D projections A61B5/0066 takes precedence
• CPC Class Codes: G01N 2021/1785 Three dimensional
• CPC Class Codes: G01N 21/453 Holographic interferometry for dimensional measurements G01B9/021 - G01B9/029
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B
• CPC Class Codes: G01N 21/6458 Fluorescence microscopy fluorescence microscopes per se G02B21/0076 and G02B21/16
• CPC Class Codes: G01N 21/65 Raman scattering
• CPC Class Codes: G01N 2201/0675 SLM
• CPC Class Codes: G02B 21/0032 Optical details of illumination, e.g. light-sources, pinholes, beam splitters, slits, fibers G02B21/0036 - G02B21/008; means for illumination of specimens in general G02B21/06
• CPC Class Codes: G02B 21/0072 details concerning resolution or correction, including general design of CSOM objectives
• CPC Class Codes: G02B 21/0076 arrangements using fluorescence or luminescence
• CPC Class Codes: G02B 26/06 for controlling the phase of light G02B26/08 takes precedence , measuring optical phase difference G01J9/00
• CPC Class Codes: G03H 1/2294 Addressing the hologram to an active spatial light modulator
• CPC Class Codes: G03H 2001/0467 Gated recording using pulsed or low coherence light source, e.g. light in flight, first arriving light

Abstract

An apparatus includes a light source configured to emit an electromagnetic wave; a spatial light modulator configured to modulate a wavefront of the electromagnetic wave to irradiate a sample; a plate with an aperture; a lens unit configured to set a focal point in the sample; a detector configured to detect light coming from the focal point of the sample through the aperture; and a controller configured to control the spatial light modulator based on the detected light by the detector.

Claims

1. An apparatus comprising:

a light source configured to emit an electromagnetic wave;

a spatial light modulator configured to modulate a wavefront of the electromagnetic wave to irradiate a sample;

a confocal system including a plate with an aperture and a lens unit configured to set a focal point in the sample;

a photodetector configured to detect a signal corresponding to an electromagnetic wave coming from the focal point of the sample through the confocal system; and

a controller configured to control the spatial light modulator to optimize the wavefront of the electromagnetic wave in such a way that the signal detected by the photodetector is enhanced,

wherein the controller is configured to control the light source in such a way that a power of the electromagnetic wave whose wavefront is optimized is different from a power of the electromagnetic wave whose wavefront is not optimized, and

wherein the controller is configured to reconstruct an image using a signal generated in response to the irradiation of an electromagnetic wave whose wavefront is optimized and power is different from the power of the electromagnetic wave whose wavefront is not optimized.

2. The apparatus according to claim 1, wherein the spatial light modulator is a liquid crystal on silicon (LCOS) or a digital micro-mirror device (DMD).

3. The apparatus according to claim 1, wherein the spatial light modulator has a plurality of segments, and the controller controls a phase value of each of the plurality of segments for optimization.

4. The apparatus according to claim 1, wherein the photodetector is a photomultiplier tube.

5. The apparatus according to claim 1, wherein the controller is configured to reconstruct the image using a photoacoustic signal as the signal generated in response to the irradiation of an electromagnetic wave whose wavefront is optimized and power is controlled.

6. The apparatus according to claim 1, wherein the controller is configured to control the spatial light modulator to optimize the wavefront of the electromagnetic wave in such a way that the signal detected by the photodetector is maximized.

7. The apparatus according to claim 1, wherein the controller is configured to control the spatial light modulator to optimize the wavefront of the electromagnetic wave in such a way that the signal detected by the photodetector is load a specified value.

8. The apparatus according to claim 1, wherein the photodetector is configured to detect a signal as a function of time corresponding to an electromagnetic wave of which wavefront is optimized coming from the focal point of the sample through the confocal system, and

wherein the controller is configured to obtain information regarding movement of a medium positioned at the focal point based on the signal as a function of time corresponding to the electromagnetic wave of which wavefront is optimized.

9. The apparatus according to claim 8, wherein the controller is configured to obtain the information regarding a speed of the medium positioned at the focal point as the information regarding movement of the medium positioned at the focal point.

10. The apparatus according to claim 8, wherein the controller is configured to obtain the information regarding blood flow as the information regarding movement of the medium positioned at the focal point.

11. The apparatus according to claim 8, wherein the controller is configured to cause a display to display the information regarding movement of the medium.

12. The apparatus according to claim 1, wherein the controller is configured to obtain the information regarding movement of the medium positioned at the focal point based on a decay of the signal corresponding to the electromagnetic wave of which wavefront is optimized.

13. The apparatus according to claim 1, wherein the controller is configured to cause a display to display the reconstructed image.

14. An apparatus comprising:

a light source configured to emit an electromagnetic wave;

a spatial light modulator configured to modulate a wavefront of the electromagnetic wave to irradiate a sample;

a lens unit configured to set a focal point in the sample;

a plate with an aperture which forms a confocal system with the lens;

a photodetector configured to detect a signal corresponding to an electromagnetic wave coming from the focal point of the sample through the confocal system; and

a controller configured to control the spatial light modulator to optimize the wavefront of the electromagnetic wave in such a way that the signal detected by the photodetector is enhanced,

wherein the controller is configured to reconstruct an image using a photoacoustic signal generated in response to the irradiation of an electromagnetic wave whose wavefront is optimized.

15. The apparatus according to claim 14, wherein the controller is configured to control the spatial light modulator to optimize the wavefront of the electromagnetic wave in such a way that the signal detected by the photodetector is maximized.

16. The apparatus according to claim 14, wherein the controller is configured to control the spatial light modulator to optimize the wavefront of the electromagnetic wave in such a way that the signal detected by the photodetector is load a specified value.