Improvement of slab-laser beam divergence by using an off-axis unstable–stable resonator

Kuba, Kazuki; Yamamoto, Takashi; Yagi, Shigenori

doi:10.1364/ol.15.000121

Cited by 25 publications

(4 citation statements)

References 9 publications

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“…An unstable ring resonator with 90°beam rotation [3,4] has been shown to have good beam quality and align-ment insensitivity, but the experimental setup is rather complicated. Different types of stable-unstable resonators [5][6][7][8] were used to improve the beam quality, but the disadvantage of such a hybrid resonator is its stable part. With increasing mirror dimensions, the problems of conventional stable resonators also occur in the stable direction of hybrid resonators.…”

Section: Introductionmentioning

confidence: 99%

COIL emission of a modified negative branch confocal unstable resonator

Pargmann¹,

Hall²,

Duschek³

et al. 2007

Appl. Opt.

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A modified negative branch confocal unstable resonator (MNBUR) was coupled to the chemical oxygen-iodine laser (COIL) device of the German Aerospace Center. It consists of two spherical mirrors and a rectangular scraper for power extraction. Experimentally measured distributions of the near- and far-field intensities and the near-field phase were found in close agreement to numerical calculations. The extracted power came up to approximately 90% of the power as expected for a stable resonator coupled to the same volume of the active medium. The output power revealed a considerable insensitivity towards tilts of the resonator mirrors and the ideal arrangement of the scraper was found to be straightforward by monitoring the near-field distributions of intensity and phase. The beam quality achieved with the MNBUR of an extremely low magnification of only 1.04 was rather poor but nevertheless in accordance with theory. The demonstrated consistency between theory and experiment makes the MNBUR an attractive candidate for lasers that allow for higher magnification. In particular, it promises high brilliance in application to 100 kW class COIL devices, superior to the conventional negative branch confocal unstable resonator.

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Section: Introductionmentioning

confidence: 99%

COIL emission of a modified negative branch confocal unstable resonator

Pargmann¹,

Hall²,

Duschek³

et al. 2007

Appl. Opt.

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“…As already mentioned, the beam quality in the wider cross-section transverse direction is intrinsically worse, given the much larger cross-section dimension, and has to be enhanced with the adoption of a specific cavity scheme such as the Hybrid Stable Unstable Resonator (HSUR) [7]- [9].…”

Section: The Edge Zig-zagged Laser: Preliminary Experimental Resultsmentioning

confidence: 99%

“…It is indeed clear that the slab design is perfectly suited for the scaling up of the extracted power by simply increasing the width of the slab rectangular cross-section. High brightness sources can be obtained using Hybrid Stable-Unstable Resonators (HSURs) [7]- [9].…”

Section: Introductionmentioning

confidence: 99%

High efficiency, Diode Pumped 170 W Nd:YAG ceramic slab laser

Lapucci¹,

Ciofini²,

Pucci³

et al. 2011

J. Eur. Opt. Soc.-Rapid Publ.

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A new thin-slab ceramic Nd:YAG laser is presented based on a non-conventional zig-zag configuration. The slab is shaped in such a way that the beam propagates internally bouncing on the thin lateral faces (Edge zig-zag). Preliminary experiments have demonstrated a power extraction of 170 W (CW) at an optical conversion efficiency of 36%. Measurements have also been performed to assess the propagation properties, at least in the thinner transverse direction, of the beam extracted with a simple stable resonator. This laser format appears as a good competitor of the more traditional face-pumped or edge-pumped zig-zag slab laser schemes.

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“…Hybrid resonators have been operated on carbon dioxide lasers and solid state lasers. 4 In general, hybrid resonators consist of two cylindrical mirrors in confocal alignment (see Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Hybrid resonator configurations for COIL

Duschek¹,

Handke²,

Hall³

et al. 2006

SPIE Proceedings

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Various schemes of geometrical coupling between optical resonator and gain medium were investigated for a 10-kW class Chemical Oxygen-Iodine Laser (COIL). Starting from theory, different types of resonator layouts were designed and optimized for COIL with a rectangular gain medium and an output coupling of about 10%. Hybrid resonators match these coupling conditions more easily than concentric unstable resonators. Compared to the negative branch type, the positive branch hybrid resonator shows very high sensitivity to the optical alignment in the unstable direction but avoids a focal line within the resonator. The obtained output power of both hybrid resonators is compared to the output power of the COIL device in a conventional stable resonator configuration. Measured margins for the sensitivity of resonator setup and alignment were found in close agreement with numerical calculations. Power density distributions were measured in the near field and in the far field. The divergence of the emitted laser beam in the unstable direction was nearly diffraction limited.

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Improvement of slab-laser beam divergence by using an off-axis unstable–stable resonator

Cited by 25 publications

References 9 publications

COIL emission of a modified negative branch confocal unstable resonator

COIL emission of a modified negative branch confocal unstable resonator

High efficiency, Diode Pumped 170 W Nd:YAG ceramic slab laser

Hybrid resonator configurations for COIL

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