LASER APPARATUS AND PHOTOACOUSTIC APPARATUS

• US 20140092932A1
• Filed: 09/24/2013
• Published: 04/03/2014
• Est. Priority Date: 10/02/2012
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Ichihara, Shigeru
• Granted Patent: US 9,131,877 B2
• Time in Patent Office: Days
• US Class Current: 372/100
• CPC Class Codes: A61B 5/14 Devices for taking samples of blood hypodermic syringes A61M5/00; Measuring characteristics of blood in vivo, e.g. gas concentration within the blood, pH-value of blood measuring of blood pressure A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/150748 Having means for aiding positioning of the piercing device at a location where the body is to be pierced means for aiding positioning of devices for bringing media into the body A61M5/427, locating blood vessels A61B5/489
• CPC Class Codes: G01H 9/00 Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
• CPC Class Codes: H01S 3/08004 incorporating a dispersive element, e.g. a prism for wavelength selection H01S3/0811, H01S3/08022 take precedence
• CPC Class Codes: H01S 3/08054 Passive cavity elements acting on the polarization, e.g. a polarizer for branching or walk-off compensation quarter-wave plates in a Q-switch laser H01S3/1124, H01S3/115
• CPC Class Codes: H01S 3/08059 Constructional details of the reflector, e.g. shape mirrors in general G02B5/08; mountings for mirrors G02B7/18
• CPC Class Codes: H01S 3/08072 Thermal lensing or thermally induced birefringence; Compensation thereof
• CPC Class Codes: H01S 3/092 of flash lamp H01S3/0937 takes precedence ; flash lamps per se H01J61/80; circuit arrangements for operating flash lamps in general H05B41/30
• CPC Class Codes: H01S 3/1026 Controlling the active medium by translation or rotation, e.g. to remove heat from that part of the active medium that is situated on the resonator axis
• CPC Class Codes: H01S 3/106 by controlling devices placed within the cavity H01S3/10076, H01S3/13 take precedence
• CPC Class Codes: H01S 3/115 using intracavity electro-optic devices
• CPC Class Codes: H01S 3/136 by controlling devices placed within the cavity

Abstract

A laser apparatus that allows selection of a wavelength of output light from a plurality of options. The laser apparatus includes: a resonator made up from an output mirror and reflection means having a plurality of reflective surfaces fixed in position; a laser medium disposed on an optical axis inside the resonator; branch means branching an optical path of a light beam formed on the optical axis when light oscillates in the laser medium into a plurality of optical paths having an end at one reflective surface of the reflection means, the branch means forming a first optical path coinciding with the optical axis when located out of the optical axis, and forming a branch path by moving the light of the optical axis parallel when located on the optical axis.

Claims

1. A laser apparatus that allows selection of a wavelength of output light from a plurality of options, comprising:

a resonator made up from an output mirror and a reflection means having a plurality of reflective surfaces fixed in position;

a laser medium disposed on an optical axis inside the resonator;

a branch means branching an optical path of a light beam formed on the optical axis when light oscillates from the laser medium into a plurality of optical paths having an end at one reflective surface of the reflection means, the branch means forming a first optical path coinciding with the optical axis when located out of the optical axis, and forming a branch path by moving the light of the optical axis parallel when located on the optical axis; and

a moving means moving the branch means between a position on the optical axis and a position out of the optical axis,

wherein the reflective surface determining a wavelength of output light.

2. The laser apparatus according to claim 1, wherein the branch means is a parallel plate that moves the optical path on the optical axis parallel by refraction.

3. The laser apparatus according to claim 2, wherein the moving means controls the parallel plate to move parallel.

4. The laser apparatus according to claim 2, wherein the moving means controls the parallel plate to rotate.

5. The laser apparatus according to claim 1, wherein

the branch means is a component that has a plurality of flat plates with different thicknesses, and forms a plurality of branch paths with different parallel displacements of the light in accordance with the thicknesses, and

the reflection means has reflective surfaces corresponding to respective branch paths.

6. The laser apparatus according to claim 1, wherein the branch means is a pair of identical wedge-shaped members that are arranged inversely.

7. The laser apparatus according to claim 1, wherein the branch means further includes a parallel plate fixedly arranged on an optical path that is formed when the branch means is located at the position on the optical axis.

8. The laser apparatus according to claim 1, wherein the plurality of reflective surfaces of the reflection means include a reflective film of dielectric material that reflects light of a wavelength corresponding to each of the reflective surfaces.

9. The laser apparatus according to claim 8, wherein the reflective surfaces of the reflection means each have a curvature that is set to reduce thermal lens effects for corresponding wavelengths.

10. The laser apparatus according to claim 1, wherein the reflection means is a prism arranged for each of the plurality of optical paths for reflecting light of a wavelength corresponding to the branch path.

11. The laser apparatus according to claim 1, wherein the reflection means is a prism having reflective surfaces of different angles corresponding to each of the plurality of optical paths.

12. The laser apparatus according to claim 1, further comprising:

a prism for changing the optical path that is arranged between the branch means and the reflection means and that includes a first surface for a light beam from the first optical path to enter, a second surface for a light beam from the branch path to enter, and a third surface for light beams that have entered the first surface and the second surface to exit,

wherein the light beams exiting from the third surface each entering a different reflective surface of the reflection means.

13. The laser apparatus according to claim 1, further comprising:

an optical sensor that detects light leaking from respective reflective surfaces of the reflection means to allow control of light emission based on a wavelength corresponding to the reflective surface from which the light is detected.

14. The laser apparatus according to claim 1, further comprising:

a photocoupler that detects whether or not the branch means is located out of the optical axis to allow control of light emission based on a wavelength determined by where the branch means is located.

15. A photoacoustic apparatus comprising

the laser apparatus according to claim 1, and

an information processing device generating property information of inside of an object based on a photoacoustic wave generated when the object is irradiated with light from the laser apparatus.