WAVELENGTH CONVERTER

• US 20200136339A1
• Filed: 12/31/2019
• Published: 04/30/2020
• Est. Priority Date: 08/22/2017
• Status: Active Grant

• Current Assignee: Gigaphoton, Inc. (Komatsu Ltd.)
• Original Assignee: Gigaphoton, Inc. (Komatsu Ltd.)
• Inventors: FUCHIMUKAI, Atsushi, WAKABAYASHI, Osamu, SASAKI, Yoichi
• Granted Patent: US 11,271,360 B2
• Time in Patent Office: Days
• CPC Class Codes: G02F 1/3505 Coatings; Housings; Supports
• CPC Class Codes: G02F 1/3507 Arrangements comprising two or more nonlinear optical devices
• CPC Class Codes: G02F 1/353 Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams
• CPC Class Codes: H01S 3/0092 Nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity nonlinear frequency conversion per se G02F1/35
• CPC Class Codes: H01S 3/027 comprising a special atmosphere inside the housing
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/06758 Tandem amplifiers
• CPC Class Codes: H01S 3/109 Frequency multiplication, e.g. harmonic generation
• CPC Class Codes: H01S 3/1608 erbium
• CPC Class Codes: H01S 3/1618 ytterbium
• CPC Class Codes: H01S 3/1643 YAG
• CPC Class Codes: H01S 3/2251 ArF, i.e. argon fluoride is comprised for lasing around 193 nm
• CPC Class Codes: H01S 3/2316 Cascaded amplifiers
• CPC Class Codes: H01S 3/2366 comprising a gas as the active medium H01S3/10092, H01S3/2383 take precedence
• CPC Class Codes: H01S 3/2375 Hybrid lasers H01S3/07 takes precedence
• CPC Class Codes: H01S 3/2391 emitting at different wavelengths

Abstract

A wavelength converter including: A. a crystal holder configured to hold a nonlinear crystal configured to convert a wavelength of a laser beam incident thereon and output the wavelength-converted laser beam; B. a first container configured to accommodate the crystal holder and include a light incident window so provided as to intersect an optical path of the laser beam incident on the nonlinear crystal and a light exiting window so provided as to intersect the optical path of the laser beam having exited out of the nonlinear crystal; C. a second container configured to accommodate the first container; D. a position adjusting mechanism configured to adjust at least a position of the first container; and E. an isolation mechanism configured to spatially isolate the light incident window and the light exiting window from the position adjusting mechanism.

Claims

1. A wavelength converter comprising:

A. a crystal holder configured to hold a nonlinear crystal configured to convert a wavelength of a laser beam incident thereon and output the wavelength-converted laser beam;

B. a first container configured to accommodate the crystal holder and include a light incident window so provided as to intersect an optical path of the laser beam incident on the nonlinear crystal and a light exiting window so provided as to intersect the optical path of the laser beam having exited out of the nonlinear crystal;

C. a second container configured to accommodate the first container;

D. a position adjusting mechanism configured to adjust at least a position of the first container; and

E. an isolation mechanism configured to spatially isolate the light incident window and the light exiting window from the position adjusting mechanism.

2. The wavelength converter according to claim 1, further comprising:

F. a first purge mechanism configured to purge an interior of the first container with a first purge gas; and

G. a second purge mechanism configured to purge an interior of the second container with a second purge gas.

3. The wavelength converter according to claim 2,

wherein the first purge mechanism includes

a first gas introducing pipe configured to pass through the second container and be connected to the first container and configured to introduce the first purge gas into the first container, and

a first gas discharging pipe configured to pass through the second container and be connected to the first container and configured to discharge the first purge gas from the first container.

4. The wavelength converter according to claim 3,

wherein the first purge gas is argon gas, helium gas, neon gas, or hydrogen gas, and

the second purge gas is nitrogen gas, argon gas, helium gas, or hydrogen gas.

5. The wavelength converter according to claim 3,

wherein the second purge mechanism includes

a second gas introducing pipe configured to introduce the second purge gas into the second container, and

a second gas discharging pipe configured to discharge the second purge gas from the second container.

6. The wavelength converter according to claim 3,

wherein the first gas introducing pipe includes a flexible introduction pipe connected to the first container and the second container and located therebetween, and

the first gas discharging pipe includes a flexible discharge pipe connected to the first container and the second container and located therebetween.

7. The wavelength converter according to claim 6,

wherein the flexible introduction pipe and the flexible discharge pipe are each a fluorine-based resin tube.

8. The wavelength converter according to claim 1,

wherein the position adjusting mechanism includes a rotational driver configured to rotate the nonlinear crystal to change an angle of incidence of the laser beam incident on the nonlinear crystal and a linear driver configured to linearly move the nonlinear crystal.

9. The wavelength converter according to claim 8,

wherein the first container is placed on the rotational driver, and the second container is placed on the linear driver.

10. The wavelength converter according to claim 9,

wherein a recess configured to accommodate the rotational driver is formed in the first container, and

the isolation mechanism is disposed between an upper end of the recess and the first container.

11. The wavelength converter according to claim 10,

wherein the isolation mechanism includes an O ring.

12. The wavelength converter according to claim 8,

wherein the second container is configured to accommodate the rotational driver and the linear driver, and

the first container is placed on the rotational driver, and the rotational driver is placed on the linear driver.

13. The wavelength converter according to claim 12,

wherein the isolation mechanism includes a bellows configured to cover a circumference of the position adjusting mechanism and disposed between the first container and the second container.

14. The wavelength converter according to claim 13,

wherein the isolation mechanism includes an O ring disposed between the bellows and the first container.

15. The wavelength converter according to claim 8,

wherein the first container is connected to the rotational driver via a through hole provided at a bottom of the first container,

the rotational driver is held by a holder provided at the bottom of the first container, and

the holder is placed on the linear driver accommodated in the second container.

16. The wavelength converter according to claim 15,

wherein the isolation mechanism includes a bellows configured to cover a circumference of the position adjusting mechanism and disposed between the first container and the second container.

17. The wavelength converter according to claim 15, further comprising:

F. a first purge mechanism configured to purge an interior of the first container with a first purge gas; and

G. a second purge mechanism configured to purge an interior of the second container with a second purge gas,

wherein the first purge mechanism holds internal pressure in the first container higher than an atmospheric pressure.

18. The wavelength converter according to claim 1,

wherein the second container accommodates a plurality of sets of the crystal holder, the first container, the position adjusting mechanism, and the isolation mechanism.

19. The wavelength converter according to claim 1,

wherein the light incident window is connected via an O ring to a light-incident-side opening provided in a body of the first container, and

a shielding film configured to shield the O ring from scattered light resulting from the laser beam is formed on the light incident window.

20. The wavelength converter according to claim 1,

wherein the nonlinear crystal is a CLBO crystal, a KBBF crystal, or a BBO crystal.