Pulsed diode-pumped solid-state laser

• US 6,418,154 B1
• Filed: 06/07/1999
• Issued: 07/09/2002
• Est. Priority Date: 06/07/1999
• Status: Expired due to Term

• Current Assignee: Coherent LaserSystems GmbH & Co., KG (Coherent Corp.)
• Original Assignee: Coherent Inc (Coherent Corp.)
• Inventors: Kneip, Axel, von Elm, Ruediger
• Primary Examiner(s): LEUNG, QUYEN PHAN
• Application Number:
  US09/327,147
• Time in Patent Office: 1,128 Days
• Field of Search: 372/75, 372/10, 372/22, 372/25, 372/26, 372/38.02, 372/38.03, 372/38.06
• US Class Current: 372/25
• CPC Class Codes: H01S 3/09415 the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping
• CPC Class Codes: H01S 3/10038 Amplitude control
• CPC Class Codes: H01S 3/115 using intracavity electro-optic devices
• CPC Class Codes: H01S 3/117 using intracavity acousto-optic devices
• CPC Class Codes: H01S 3/1312 by controlling the optical pumping

Abstract

A pulsed, solid laser having a solid-state gain-medium and Q-switch is optically-pumped by a diode-laser array controlled to deliver pump-light pulses to the gain-medium. The Q-switch and the diode-laser array are cooperatively controlled by a controller such that laser output-pulses produced in response to pump-light pulses have the same energy independent of the time-interval between laser output-pulses. Pump-light pulses may be provided by the controller operating a switchable current supply which supplies current-pulses to the diode-laser array for causing pump-light pulses to be delivered to the gain-medium. A controller may also be arranged to drive the diode-laser to provide continuous pump-light output and to operate a light modulator located between the diode-laser array and the gain-medium to cause pump-light pulses to be delivered to the gain medium.

Claims

1. A laser, comprising:

a laser resonator having a solid-state gain medium;

a source of pump-light for energizing said gain medium, said pump-light source arranged to provide a series of pump-light pulses for energizing said solid-state gain-medium, each of said pump-light pulses having the same duration, and said pump-light pulses having variable time-periods therebetween;

a Q-switch located in said laser resonator, said Q-switch arranged to retard operation of said laser resonator until one of said pump-light pulses is terminated, said termination of said pump-light pulse providing a trigger signal for opening said Q-switch thereby allowing delivery by said laser resonator of a laser output-pulse responsive to said pump-light pulse; and

said pump-light source having an essentially constant output throughout each pump-light pulse, and said pump-light source being further arranged to deliver sufficient additional pump-light to said gain-medium, between termination of each said pump-light pulse and initiation of a subsequent pump-light pulse, with said Q-switch arranged to prevent generation of laser radiation in response to said delivery, such that gain in said gain-medium is the same at the initiation of each pump-light pulse independent of the time interval between said pump-light pulses, whereby each laser output-pulse has about the same energy, independent of the time-period between laser output-pulses.

2. The laser of claim 1, wherein said pump-light source is one of a diode-laser and a diode-laser array.

3. The laser of claim 2, wherein said gain-medium is a gain-medium selected from the group of gain media consisting of Nd:

YAG, Nd;

YV0₄ and Nd;

YLF.

4. A laser, comprising:

a laser resonator including a solid-state gain medium;

a diode-laser array driven by a regulated current-supply and a controller;

said controller arranged such that said current-supply delivers a series of current-pulses to said diode-laser array, said diode-laser array generating a series of pump-light pulses responsive to said series of current-pulses for energizing said solid-state gain-medium;

said controller further arranged such that each of said current-pulses and and corresponding pump-light pulses has the same duration, and such that said current-pulses and corresponding pump-light pulses have a variable time-period therebetween;

a Q-switch located in said laser resonator, said Q-switch arranged to retard operation of said laser resonator until one of said current-pulses is terminated, said termination of said current-pulse providing a trigger-signal for opening said Q-switch, thereby allowing delivery by said laser resonator of a laser output-pulse; and

said controller further arranged such that said diode-laser array has an essential constant output throughout each pump-light pulse and also arranged such that said current-supply provides a predetermined minimum level of current to said diode-laser array between said current-pulses with said Q-switch closed to prevent generation of laser radiation in the resonator, said minimum level of current being such that said diode laser array provides sufficient additional pump-light to said gain-medium between said pump-light pulses, without generating laser radiation, to maintain a predetermined minimum gain level in said gain-medium, whereby each laser output-pulse has about the same energy, independent of the time-period between laser output-pulses.

5. The laser of claim 4, wherein said gain-medium is a gain-medium selected from the group of gain media consisting of Nd:

YAG, Nd;

YV0₄ and ND;

YLF.

6. The laser of claim S wherein said laser output-pulses are delivered at a pulse-repetition rate less than about 200 kilohertz.

7. A laser, comprising:

a laser resonator including a solid-state gain medium;

a diode-laser array driven by a regulated current-supply and a controller;

said controller arranged such that said current-supply delivers, a series of current-pulses to said diode-laser array, said diode-laser array responsively generating a series of pump-light pulses for energizing said solid-state gain-medium;

said controller further arranged such that there is a constant tie-interval between initiation of each of said current-pulses and corresponding pump-light pulses and such that each of said current-pulses and corresponding pump-light pulses has one of a first duration and a second duration, said second duration being shorter than said first duration, and said constant time-interval being defined as a clock-period;

a Q-switch located in said laser resonator, said Q-switch arranged to retard operation of said laser resonator until one of said current-pulses of said first duration is terminated, said termination of said first-duration current-pulse providing a trigger-signal for opening said Q-switch, thereby allowing delivery by said laser resonator of a laser output-pulse; and

said Q-switch remaining closed on termination of said current pulses of said second duration, and said first and second pulse durations being selected such that residual gain in said gain-medium is the same at the initiation of each current-pulse, whereby said laser output-pulses have a time-interval therebetween equal to an integer multiple of said clock-period and each of said laser output-pulses has about the same energy, independent of the time-interval therebetween.

8. A laser, comprising:

a laser resonator including a Q-switch, and a solid-state gain-medium;

a diode-laser array for optically pumping said gain-medium, said diode-laser array being driven by a switchable, regulated current-supply and a controller;

said current-supply controlled by said controller to initiate delivery of current-pulses to said diode-laser array, said diode-laser array correspondingly providing pump-light pulses responsive to said current-pulses for optically pumping said gain-medium;

said current-pulses and corresponding pump-light pulses being of essentially constant magnitude and duration, and between said pump-light pulses said current-supply being controlled by said controller such that said diode-laser array provides sufficient additional pump-light to said gain-medium, with said Q-switch closed to prevent generation of laser radiation, such that gain in said gain-medium is the same at the initiation of each pump-light pulse; and

said Q-switch being arranged cooperative with said controller and said current-supply such that said Q-switch is opened at the termination of each current-pulse for delivering a laser output-pulse from said laser resonator, whereby in a series of said laser output-pulses delivered by said laser resonator, each thereof has the same energy independent of the time-interval therebetween.

9. A laser, comprising:

a laser resonator including a solid-state gain medium;

a diode-laser array driven by a regulated current-supply and a controller and provide a continuous pump-light output;

a light-modulator located between said diode-laser array and said solid state gain-medium in the path of said pump-light output of said diode-laser array;

said controller arranged to operate said light-modulator such that said pump-light output from said diode-laser array is delivered to said gain medium as a series of pump-light pulses for exciting said gain medium;

said controller further arranged that there is a constant time-interval between initiation of each of said pump-light pulses and such that each of said pump-light pulses has one of a first duration and a second duration, said second duration being shorter than said first duration, and said constant time-interval defined as a clock-period;

a Q-switch located in said laser resonator, said Q-switch arranged to retard operation of said laser resonator until one of said pump-light pulses of said first duration is terminated, said termination of said first-duration pump-light pulse providing a trigger-signal for opening said Q-switch, thereby allowing delivery by said laser resonator of a laser output-pulse; and

said Q-switch remaining closed on termination of said current pulses of said second duration, and said fist and second pump-light pulse durations being selected such that residual gain in said gain-medium is the same at the initiation of each pump-light pulse, whereby said laser output-pulses have a time-interval therebetween equal to an integer multiple of said clock-period and each of said laser output-pulses has about the same energy, independent of the time-interval therebetween.

10. The laser of claim 9, wherein said laser output-pulses are delivered at a pulse-repetition rate greater than about 200 kilohertz.