| 1. |
- Ha Ryu, Jae, et al.
(författare)
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Beam stability of buried-heterostructure quantum cascade lasers employing HVPE regrowth
- 2021
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Ingår i: Optics Express. - : The Optical Society. - 1094-4087. ; 29:2, s. 2819-2826
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of beam stability for mid-infrared (IR)-emitting quantum cascade lasers (QCLs) are important for applications that require the beam to travel through air to remote targets, such as free-space communication links. We report beam-quality measurement results of narrow-ridge, 4.6 mu m-emitting buried-heterostructure (BH) QCLs fabricated using ICP etching and HVPE regrowth. Beam-quality measurements under QCW operation exhibit M-2 < 1.2 up to 1 W for similar to 5 mu m-wide ridges. 5 mu m-wide devices display some small degree of centroid motion with increasing output power (< 0.125 mrad), which corresponds to a targeting error of similar to 1.25 cm over a distance of 100 m.
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| 2. |
- Ryu, Jae Ha, et al.
(författare)
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Reverse-Taper Mid-Infrared Quantum Cascade Lasers for Coherent Power Scaling
- 2022
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Ingår i: IEEE Photonics Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1943-0655. ; 14:3
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Tidskriftsartikel (refereegranskat)abstract
- We present a reverse-taper quantum cascade laser (QCL) emitting at 4.6 mu m, a novel-geometry device that can scale the output power while maintaining good beam quality. Buried-ridge waveguides with tapered and straight regions were formed by ICP etching and HVPE regrowth - the tapered region scales the output power, while the emitting facet is located at the narrow-end taper section, which provides mode filtering by suppressing high-order spatial modes. Beam profiles were observed under quasi-continuous-wave (QCW)/CW operation and beam quality (M-2) measurements along with beam-stability measurements were performed - a small degree of collimated-beam centroid movement (<0.46 mrad, peak-to-peak) was observed, along with M-2 values close to 1 up to similar to 1 W QCW power. Devices of shorter cavity lengths were also investigated, indicating that the output power scales with the core-region volume but results in a small increase in angular deviation.
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| 3. |
- Ryu, Jae Ha, et al.
(författare)
-
Reverse-Taper Mid-IR Quantum Cascade Lasers for Coherent Power Scaling
- 2021
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Ingår i: 2021 27th International Semiconductor Laser Conference (ISLC). - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- Novel-geometry, 4.6 mu m-emitting BH QCLs were fabricated, where a tapered region scales the output power and, ahead of the emitting aperture, a narrow section provides mode filtering for suppressing high-order spatial modes. Beam-stability measurements indicate a small degree of collimated-beam centroid motion (< 0.25 mrad).
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