Apparatus and method for irradiating a medium

• US 9,304,490 B2
• Filed: 05/27/2011
• Issued: 04/05/2016
• Est. Priority Date: 05/27/2011
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Masumura, Takahiro
• Primary Examiner(s): PENDLETON, DIONNE
• Application Number:
  US13/118,097
• Publication Number:
  US 20120300608A1
• Time in Patent Office: 1,775 Days
• Field of Search: 356/450, 356/456, 356/457, 356/453, 356/484, 356485-489, 356/496, 356/504, 356/512, 356/513, 356/521, 369/100, 369/102, 369/103, 369/86, 369/87, 369/90, 369/106, 369/107, 36910901-11003, 36911201-11202, 36911203-11205, 369/112.1, 36911215-11216
• US Class Current: 1/1
• CPC Class Codes: G01N 2021/1706 in solids
• CPC Class Codes: G01N 2021/1727 Magnetomodulation
• CPC Class Codes: G01N 21/1717 with a modulation of one or more physical properties of the sample during the optical investigation, e.g. electro-reflectance
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B
• CPC Class Codes: G03H 1/0465 Particular recording light; Beam shape or geometry G03H1/06 takes precedence
• CPC Class Codes: G03H 2001/0072 for wavefront conjugation wherein the hologram generates a wavefront conjugating a predetermined object, e.g. null testing, positioning, comparative holography
• CPC Class Codes: G03H 2001/0083 for restoring distorted objects, e.g. restoring objects through scattering media
• CPC Class Codes: G11B 2220/2504 Holographic discs; Holographic digital data storage [HDDS]
• CPC Class Codes: G11B 7/0065 Recording, reproducing or erasing by using optical interference patterns, e.g. holograms

Abstract

A method for irradiating a medium with a wave which is designed to focus on a particular portion in the medium, the method includes: irradiating the medium with an electromagnetic wave which is scattered in the medium, and is not designed to focus on the particular portion in the medium; detecting a first signal caused by irradiating the medium with the electromagnetic waver; irradiating the medium with a reconstructed wave which is designed to focus on the particular portion in the medium; detecting a second signal caused by irradiating the medium with the reconstructed wave; and monitoring, based on the first and second signals, that the particular portion is irradiated by the reconstructed wave.

Claims

1. A method for irradiating a medium with an electromagnetic wave which is designed to focus on a particular portion in the medium, the method comprising:

irradiating the medium with a first electromagnetic wave which is scattered in the medium, and is not designed to focus on the particular portion in the medium;

detecting using at least one ultrasound detector a first photoacoustic signal caused by irradiating the medium with the first electromagnetic wave, the first photoacoustic signal being sound of ultrasonic frequency;

irradiating the medium with a second electromagnetic wave which is designed to focus on the particular portion in the medium;

detecting using the at least one ultrasound detector a second photoacoustic signal caused by irradiating the medium with the second electromagnetic wave, the second photoacoustic signal being sound of ultrasonic frequency; and

monitoring a light distribution of the particular portion, which is irradiated by the second electromagnetic wave, based on a ratio of the second photoacoustic signal to the first photoacoustic signal.

2. The method for irradiating the medium according to claim 1, wherein the first photoacoustic signal includes a signal from the particular portion and a first area around the particular portion.

3. The method for irradiating the medium according to claim 2, wherein the second photoacoustic signal includes a signal from the particular portion and a second area around the particular portion.

4. The method for irradiating the medium according to claim 3, wherein the first area is the same as the second area.

5. The method for irradiating the medium according to claim 2, further comprising setting the first area in the medium to be detected with the first photoacoustic signal.

6. The method for irradiating the medium according to claim 1, wherein the detecting of the first photoacoustic signal and the detecting of the second photoacoustic signal are executed repeatedly while the monitoring.

7. The method for irradiating the medium according to claim 1, wherein each of the first and second electromagnetic waves is a pulse wave.

8. The method for irradiating the medium according to claim 1, wherein the first electromagnetic wave comprises a pulse wave to cause the first photoacoustic signal, and the second electromagnetic wave comprises a pulse wave to cause the second photoacoustic signal in the medium, and the ratio of the second photoacoustic signal to the first photoacoustic signal is calculated while the monitoring.

9. The method for irradiating the medium according to claim 1, wherein the monitoring includes comparing the second photoacoustic signal with the first photoacoustic signal.

10. An apparatus comprising:

a light source configured to irradiate a medium with an electromagnetic wave, and to be used for a reference wave;

a modulator comprising an ultrasound device configured to modulate a frequency of the electromagnetic wave at a particular portion in the medium;

a first detector configured to obtain information related to an interference pattern formed by interference of the modulated electromagnetic wave with the reference wave;

a generator configured to generate a first electromagnetic wave which is scattered in the medium, and is not designed to focus on the particular portion in the medium, and configured to generate a second electromagnetic wave based on the information obtained by the first detector, wherein the second electromagnetic wave is designed so as to focus on the particular portion in the medium;

at least one ultrasound detector which detects sound waves of ultrasonic frequency, the at least one ultrasound detector being configured to detect a first photoacoustic signal from the medium, caused by the first electromagnetic wave, and configured to detect a second photoacoustic signal from the medium, caused by the second electromagnetic wave, the first photoacoustic signal and the second photoacoustic signal being sound of ultrasonic frequency; and

a monitor configured to monitor a light distribution of the particular portion, which is irradiated by the second electromagnetic wave, based on a ratio of the second photoacoustic signal to the first photoacoustic signal.

11. The apparatus according to claim 10, wherein the generator comprises a light source and a spatial light modulator to form the second electromagnetic wave.

12. An apparatus comprising:

a light source configured to irradiate a medium with an electromagnetic wave, and to be used for a reference wave;

a modulator comprising an ultrasound device configured to modulate a frequency of the electromagnetic wave at a particular portion in the medium;

a holographic material configured to acquire information related to an interference pattern formed by interference of the modulated electromagnetic wave with the reference wave, and to generate a reconstructed wave based on the acquired information, wherein the reconstructed wave is an electromagnetic wave which is designed so as to focus on the particular portion in the medium; and

at least one ultrasound detector which detects sound of ultrasonic frequency, the at least one ultrasound detector being configured to detect a first photoacoustic signal from the medium when an electromagnetic wave, which is scattered in the medium and is not designed to focus on the particular portion in the medium, irradiates the medium, and configured to detect a second photoacoustic signal from the medium, caused by the reconstructed wave, the first photoacoustic signal and the second photoacoustic signal being sound of ultrasonic frequency; and

a monitor configured to monitor a light distribution of the particular portion, which is irradiated by the second electromagnetic wave, based on a ratio of the second photoacoustic signal to the first photoacoustic signal.

13. An apparatus comprising:

a light source configured to irradiate a medium with an electromagnetic wave, and to be used for a reference wave;

a modulator comprising an ultrasound device configured to modulate a frequency of the electromagnetic wave at a particular portion in the medium;

a holographic material holding unit configured to hold a holographic material configured to acquire information related to an interference pattern formed by interference of the modulated electromagnetic wave with the reference wave and to generate a reconstructed wave based on the acquired information, wherein the reconstructed wave is an electromagnetic wave which is designed so as to focus on the particular portion in the medium;

at least one ultrasound detector which detects sound of ultrasonic frequency, the at least one ultrasound detector being configured to detect a first photoacoustic signal from the medium when an electromagnetic wave, which is scattered in the medium and is not designed to focus on the particular portion in the medium, irradiates the medium, and configured to detect a second photoacoustic signal from the medium, caused by the reconstructed wave, the first photoacoustic signal and the second photoacoustic signal being sound of ultrasonic frequency; and

a monitor configured to monitor a light distribution of the particular portion, which is irradiated by the second electromagnetic wave, based on a ratio of the second photoacoustic signal to the first photoacoustic signal.

14. An apparatus for irradiating a medium with an electromagnetic wave which is designed to focus on a particular portion in the medium, the apparatus comprising:

a first irradiating unit configured to irradiate the medium with a first electromagnetic wave which is scattered in the medium, and is not designed to focus on the particular portion in the medium;

a second irradiating unit configured to irradiate the medium with a second electromagnetic wave which is designed to focus on the particular portion in the medium;

at least one ultrasound detector configured to detect a first photoacoustic signal caused by irradiating the medium with the first electromagnetic wave and a second photoacoustic signal caused by irradiating the medium with the second electromagnetic wave, each of the first photoacoustic signal and the second photoacoustic signal being sound of ultrasonic frequency; and

a monitoring unit configured to monitor a light distribution of the particular portion, which is irradiated by the second electromagnetic wave, based on a ratio of the second photoacoustic signal to the first photoacoustic signal.