Marco Gaulke

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Gaulke

First Name

Marco

ORCID

0000-0002-0676-6483

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Publications 1 - 10 of 53

SESAMs for High-Power Ho-Doped Lasers at 2.1 µm
Heidrich, Jonas; Gaulke, Marco; Alaydin, B. Ozgur; et al. (2022)
Technical Digest Series ~ Optica High-brightness Sources and Light-driven Interactions Congress 2022
We present a high-precision (<0.03%) nonlinear reflectivity and pump-probe characterization of InGaSb quantum-well-based SESAMs for high-power 2.1 μm Ho-doped lasers. The SESAMs have ~1% modulation depth, high saturation fluences and fast recovery times.
Two Gigahertz Femtosecond Cr:ZnS Oscillator at 2.4 µm with 0.8-W Average Output Power
Barh, Ajanta; Alaydin, Özgür; Heidrich, Jonas; et al. (2021)
OSA Technical Digest ~ Conference on Lasers and Electro-Optics
We present a SESAM mode-locked self-starting Cr:ZnS oscillator delivering ~ 255 fs transform limited pulses at record high repetition rate above 2 GHz with average output power of 0.8 W at 2.4 µm.
Impact of Wavelength, Strain, and Barrier Materials on the Recovery Dynamics of GaSb-based SESAMs
Schuchter, Maximilian C.; Gaulke, Marco; Huwyler, Nicolas; et al. (2024)
2024 IEEE 29th International Semiconductor Laser Conference (ISLC)
We present a rigorous study on 2 mu m - 2.4 mu m GaSb-based SESAMs, adjusting quantum well design and MBE growth parameters. We discover that strain-induced defects and barrier materials significantly affect recovery dynamics, revealing distinct mechanisms notably different from the well-studied GaAs-based SESAMs.
High average output power from a backside-cooled 2-µm InGaSb VECSEL with full gain characterization
Gaulke, Marco; Heidrich, Jonas; Alaydin, Özgür; et al. (2022)
Proceedings of SPIE ~ Vertical External Cavity Surface Emitting Lasers (VECSELs) XI
We report record performance and full gain characterization of an optically pumped continuous wave InGaSb VECSEL operating around 2 µm. Our flip-chip processed and backside-cooled VECSEL performs similar to intracavity heatspreader cooling and obtained even similar thermal resistance of only 3.45 KW-1 and an average output power of >800 mW. Our gain characterization setups can cover a wavelength range from 1.9 µm to 3 µm. Linear and nonlinear gain characteristics are measured as a function of wavelength, fluence, pump power and heatsink temperature. 2-µm VECSEL chips with different strategies in heat management are compared and theoretical predictions are in good agreement.
High-power low-noise 2-GHz femtosecond laser oscillator at 2.4 µm
Barh, Ajanta; Alaydin, Özgür; Heidrich, Jonas; et al. (2022)
Optics Express
Femtosecond lasers with high repetition rates are attractive for spectroscopic applications with high sampling rates, high power per comb line, and resolvable lines. However, at long wavelengths beyond 2 µm, current laser sources are either limited to low output power or repetition rates below 1 GHz. Here we present an ultrafast laser oscillator operating with high output power at multi-GHz repetition rate. The laser produces transform-limited 155-fs pulses at a repetition rate of 2 GHz, and an average power of 0.8 W, reaching up to 0.7 mW per comb line at the center wavelength of 2.38 µm. We have achieved this milestone via a Cr2+-doped ZnS solid-state laser modelocked with an InGaSb/GaSb SESAM. The laser is stable over several hours of operation. The integrated relative intensity noise is 0.15% rms for [10 Hz, 100 MHz], and the laser becomes shot noise limited (-160 dBc/Hz) at frequencies above 10 MHz. Our timing jitter measurements reveal contributions from pump laser noise and relaxation oscillations, with a timing jitter of 100 fs integrated over [3 kHz, 100 MHz]. These results open up a path towards fast and sensitive spectroscopy directly above 2 µm.
Strain-engineered vertical emitting InGaAsSb quantum well lasers at 2–2.4 µm: in-well vs. barrier pumping, silicate bonding, and thermal optimization
Schuchter, Maximilian C.; Huwyler, Nicolas; Golling, Matthias; et al. (2025)
Optics Express
We present a comprehensive study of continuous-wave (cw) lasing in GaSb-based membrane external cavity surface emitting lasers (MECSELs) operating in the 2.0–2.4 µm range. Using both in-well and barrier pumping, we investigate the influence of quantum well (QW) strain in eight InGaAsSb-based MECSEL structures. A key advance is the implementation of silicate bonding, which improves fabrication yield from <10% (for direct bonding) to >60% by relaxing surface flatness requirements of GaSb wafers. In addition, we show that only compressively strained QWs with lattice mismatch >1% lase. This is supported by theoretical calculations showing that the imbalance between the density of states (DOS) in the conduction and valence bands limits the ability to reach population inversion, even though sufficient TE-polarized gain is available in all structures. At 2 µm, in-well and barrier pumping provide similar slope efficiencies (∼29% over absorbed power), but in-well pumping achieves a record-low thermal resistance of 0.5 ± 0.1 K/W by eliminating pump-absorbing barrier layers. At 2.35 µm, slope efficiency drops (∼6.8% for in-well, ∼10.7% for barrier pumping), likely due to increased Auger recombination at longer wavelength. The in-well design maintains superior thermal performance (0.6 ± 0.2 K/W thermal resistance). These results position in-well pumped MECSELs as a thermally efficient, wavelength-scalable platform for short-wave infrared (SWIR) applications including gas sensing, medical diagnostics, and molecular spectroscopy.
GaSb-based SESAM mode-locked upconversion-pumped Thulium Laser at 2308 nm
Tyazhev, Aleksey; Gaulke, Marco; Loiko, Pavel; et al. (2023)
Technical Digest Series ~ Conference on Lasers and Electro-Optics 2023
A thulium laser operating on the 3H4→3H5 transition with upconversion pumping by an ytterbium-fiber laser is passively mode-locked by an GaSb-based SESAM delivering 1.19 ps pulses at 2308 nm with 252 mW average output power.
2.04-µm single and dual-comb modelocked InGaSb-MIXSEL
Gaulke, Marco; Heidrich, Jonas; Huwyler, Nicolas; et al. (2023)
2023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)
Passively modelocked, optically pumped semiconductor disk lasers also referred to as VECSELs or MIXSELs combine the wavelength versatility and wafer scalability of semiconductors, together with a high beam quality of vertical emitters and a good average output power [1, 2]. Typically, a V-shaped cavity is used for SESAM-modelocked VECSELs. This is simplified to a straight linear cavity with MIXSELs, for which the SESAM is integrated into the VECSEL chip.
Modelocked InGaSb-MIXSEL at 2.04 µm
Gaulke, Marco; Heidrich, Jonas; Huwyler, Nicolas; et al. (2023)
OSA Technical Digest ~ 2023 Conference on Lasers and Electro-Optics (CLEO)
We present the first modelocked, backside-cooled InGaSb-MIXSEL operating at 2035 nm, producing fundamentally modelocked pulses of 1.5 ps with average output power up to 27 mW at 3.9 GHz repetition rate.
Femtosecond pulses from a backside-cooled 2-µm, GDD balanced InGaSb VECSEL
Gaulke, Marco; Heidrich, Jonas; Huwyler, Nicolas; et al. (2023)
Proceedings of SPIE ~ Vertical External Cavity Surface Emitting Lasers (VECSELs) XII
We report on a SESAM modelocked GDD balanced VECSEL embedding the active region in quaternary Al15Ga85AsSb. The GDD is flattened by a multilayer semiconductor dielectric top-coating allowing for stable femtosecond operation with a standard SESAM and high-quality YAG Brewster windows. We avoid tradeoffs that would limit the output power. This GDD balanced VECSEL is the next step towards higher level of integration: pump-DBR implementation, demonstration of 1:1 modelocking, and absorber integration will yield a 2-µm MIXSEL, where gain medium and absorber are grown in one monolithic structure.

Publications 1 - 10 of 53

Marco Gaulke

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