Kilohertz pulse repetition frequency slab Ti:sapphire lasers with high average power (10 W)

William J. Wadsworth, David W. Coutts, Colin E. Webb

Research output: Contribution to journalArticleResearchpeer-review

Abstract

High-average-power broadband 780-nm slab Ti:sapphire lasers, pumped by a kilohertz pulse repetition frequency copper vapor laser (CVL), were demonstrated. These lasers are designed for damage-free power scaling when pumped by CVL’s configured for maximum output power (of order 100 W) but with poor beam quality (M2 300). A simple Brewster-angled slab laser side pumped by a CVL produced 10-W average power (1.25-mJ pulses at 8 kHz) with 4.2-nsFWHMpulse duration at an absolute efficiency of 15% (68-W pump power). Thermal lensing in the Brewster slab laser resulted in multitransverse mode output, and pump absorption was limited to 72% by the maximum doping level for commercially available Ti:sapphire (0.25%). A slab laser with a multiply folded zigzag path was therefore designed and implemented that produced high-beam-quality (TEM00-mode) output when operated with cryogenic cooling and provided a longer absorption path for the pump. Excessive scattering of the Ti:sapphire beam at the crystal surfaces limited the efficiency of operation for the zigzag laser, but fluorescence diagnostic techniques, gain measurement, and modeling suggest that efficient power extraction (>15 W TEM00, .23% efficiency) from this laser would be possible for crystals with an optical quality surface polish.

LanguageEnglish
Pages6904-6911
Number of pages8
JournalApplied Optics
Volume38
Issue number33
DOIs
Publication statusPublished - 20 Nov 1999
Externally publishedYes

Fingerprint

Sapphire
Laser pulses
repetition
sapphire
slabs
Lasers
pulses
lasers
Beam quality
Vapors
Pumps
vapors
pumps
Copper
copper
output
cryogenic cooling
Gain measurement
Crystals
thermal lensing

Bibliographical note

This paper was published in Applied optics and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-38-33-6904. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.

Cite this

Wadsworth, William J. ; Coutts, David W. ; Webb, Colin E. / Kilohertz pulse repetition frequency slab Ti:sapphire lasers with high average power (10 W). In: Applied Optics. 1999 ; Vol. 38, No. 33. pp. 6904-6911.
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abstract = "High-average-power broadband 780-nm slab Ti:sapphire lasers, pumped by a kilohertz pulse repetition frequency copper vapor laser (CVL), were demonstrated. These lasers are designed for damage-free power scaling when pumped by CVL’s configured for maximum output power (of order 100 W) but with poor beam quality (M2 300). A simple Brewster-angled slab laser side pumped by a CVL produced 10-W average power (1.25-mJ pulses at 8 kHz) with 4.2-nsFWHMpulse duration at an absolute efficiency of 15{\%} (68-W pump power). Thermal lensing in the Brewster slab laser resulted in multitransverse mode output, and pump absorption was limited to 72{\%} by the maximum doping level for commercially available Ti:sapphire (0.25{\%}). A slab laser with a multiply folded zigzag path was therefore designed and implemented that produced high-beam-quality (TEM00-mode) output when operated with cryogenic cooling and provided a longer absorption path for the pump. Excessive scattering of the Ti:sapphire beam at the crystal surfaces limited the efficiency of operation for the zigzag laser, but fluorescence diagnostic techniques, gain measurement, and modeling suggest that efficient power extraction (>15 W TEM00, .23{\%} efficiency) from this laser would be possible for crystals with an optical quality surface polish.",
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Kilohertz pulse repetition frequency slab Ti:sapphire lasers with high average power (10 W). / Wadsworth, William J.; Coutts, David W.; Webb, Colin E.

In: Applied Optics, Vol. 38, No. 33, 20.11.1999, p. 6904-6911.

Research output: Contribution to journalArticleResearchpeer-review

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