Laser Systems And Related Methods

• US 20180254601A1
• Filed: 05/07/2018
• Published: 09/06/2018
• Est. Priority Date: 11/28/2013
• Status: Active Grant

• Current Assignee: Candela Corporation
• Original Assignee: Candela Corporation
• Inventors: Bhawalkar, Jayant D., Shang, Xiaoming
• Granted Patent: US 10,644,476 B2
• Time in Patent Office: Days
• CPC Class Codes: H01S 2301/02 ASE (amplified spontaneous emission), noise; Reduction thereof
• CPC Class Codes: H01S 3/005 Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B
• CPC Class Codes: H01S 3/0071 Beam steering, e.g. whereby a mirror outside the cavity is present to change the beam direction
• 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 3/061 with elliptical or circular cross-section and elongated shape, e.g. rod
• CPC Class Codes: H01S 3/0612 Non-homogeneous structure H01S3/07 takes precedence
• CPC Class Codes: H01S 3/0617 having a varying composition or cross-section in a specific direction
• CPC Class Codes: H01S 3/0625 Coatings on surfaces other than the end-faces
• CPC Class Codes: H01S 3/0627 the resonator being monolithic, e.g. microlaser
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/08081 Unstable resonators
• 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 3/094053 Fibre coupled pump, e.g. delivering pump light using a fibre or a fibre bundle
• CPC Class Codes: H01S 3/094061 Shared pump, i.e. pump light of a single pump source is used to pump plural gain media in parallel
• CPC Class Codes: H01S 3/094069 Multi-mode pumping
• CPC Class Codes: H01S 3/094076 Pulsed or modulated pumping H01S3/1024 takes precedence
• CPC Class Codes: H01S 3/10023 by functional association of additional optical elements, e.g. filters, gratings, reflectors
• CPC Class Codes: H01S 3/109 Frequency multiplication, e.g. harmonic generation
• CPC Class Codes: H01S 3/1115 using intracavity saturable absorbers
• CPC Class Codes: H01S 3/113 using intracavity saturable absorbers
• CPC Class Codes: H01S 3/13013 : by controlling the optical pumping
• CPC Class Codes: H01S 3/1312 : by controlling the optical pumping
• CPC Class Codes: H01S 3/1611 : neodymium
• CPC Class Codes: H01S 3/1633 : BeAl2O4, i.e. Chrysoberyl
• CPC Class Codes: H01S 3/1643 : YAG
• CPC Class Codes: H01S 3/2308 : Amplifier arrangements, e.g. MOPA

Abstract

A MOPA laser system that includes a seed laser configured to output pulsed laser light, an amplifier configured to receive and amplify the pulsed laser light emitted by the seed laser; and a pump laser configured to deliver a pump laser beam to both the seed laser and the amplifier and a variable attenuator configured to eliminate missing Q-switched pulses.

Claims

1. A high-energy laser system comprising:

a seed laser constructed and arranged to output a sub-nanosecond pulsed laser beam;

an amplifier constructed and arranged to receive and amplify a sub-nanosecond pulsed laser light emitted by the seed laser;

a solid state pump laser constructed and arranged to deliver a pump laser beam to both the seed laser and the amplifier via at least one optical fiber; and

a variable attenuator configured to adjust pump beam energy for the seed laser to avoid missing Q-switched pulses.

2. The high-energy laser system of claim 1 wherein the variable attenuator is also configured to prevent generation of multiple Q-switched pulses.

3. The high-energy laser system of claim 1 wherein the variable attenuator is an actively controlled variable attenuator.

4. The high-energy laser system of claim 1, wherein pulses emitted by solid state pump laser have constant energy, and wherein the variable attenuator is used to adjust a pump beam energy conducted to at least the amplifier.

5. The high-energy laser system of claim 1, wherein the variable attenuator is disposed between the seed laser and the amplifier.

6. The high-energy laser system of claim 1 wherein the variable attenuator is diffusion bonded to laser rod and is used as a passive Q-switch.

7. The high-energy laser system of claim 1, wherein the solid state pump laser is an Alexandrite laser pumped by one or more flash lamps.

8. The high-energy laser system of claim 1, wherein the seed laser comprises:

at least a gain medium; and

a passive Q-switch.

9. The high-energy laser system of claim 1, wherein the solid state pump laser is configured to generate a pulse energy greater than 1 joule with a pulse duration shorter than 0.5 millisecond.

10. The high-energy laser system of claim 1, wherein pulses of the solid state pump laser emitted by the solid state pump laser have constant energy, and wherein a variable attenuator is used to adjust the pump beam energy conducted to at least an amplifier.

11. The high-energy laser system of claim 1, further comprising a variable attenuator configured to passively adjust pumping energy to the seed laser, wherein an output energy of the pump laser is held constant.

12. A method of generating laser pulses comprising:

generating pulsed laser light using a seed laser;

directing the pulsed laser light to an amplifier;

amplifying the pulsed laser light with the amplifier; and

operating a pump laser to provide pumping energy to both the seed laser and the amplifier; and

operating a variable attenuator to adjust pump beam energy for the seed laser to avoid missing Q-switched pulses.

13. The method according to claim 12, wherein operating the pump laser comprises generating the pumping energy of greater than 1 J with a pulse duration shorter than 0.5 millisecond.

14. The method according to claim 12, further comprising coupling the pump energy emitted by the pump laser to one or more multimode optical fibers and conducting the pump energy to the seed laser and the amplifier.

15. The method according to claim 12, further comprising controlling a passive adjustment of beam energy of the pump laser with a variable attenuator to the seed laser.

16. The method according to claim 12, further comprising employing an electronic mechanism configured to ensure a single output laser radiation pulse by terminating a flash lamp drive current in the pump laser upon optical detection of an output pulse from at least one of the seed laser and the amplifier.

17. The method according to claim 12, further comprising enabling a spatial overlap between a seed laser beam and pumped gain region in the amplifier by employing the same fiber to deliver the pumping energy and the pulsed laser light emitted by the seed laser to the amplifier.