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Linewidth Enhancement Factor of Mid-IR Quantum Cascade Lasers
(2021)2021 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)Schawlow and Townes theorized that the ratio between the spontaneous emission and stimulated emission in a semiconductor laser defines its linewidth lower limit [1] . However, experiments showed that this intrinsic linewidth is larger, which was later demonstrated to be due to the coupling between the optical gain and the phase noise [2] . The linewidth enhancement factor (LEF) was introduced to quantify this process and as a correction ...Other Conference Item -
Coherent mid-infrared dual-comb spectroscopy enabled by optical injection locking of quantum cascade laser frequency combs
(2021)2021 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)Mid-infrared frequency combs are emerging as powerful tool for broadband spectroscopy in the molecular fingerprint region. Dual-comb spectroscopy is particularly promising due to its high temporal and spectral resolution. In many practical applications, quantum cascade laser (QCL) frequency combs [1] are the source of choice, because they are electrically pumped, have a small footprint and offer an unrivalled brightness. Albeit being a ...Other Conference Item -
Coherent Broadening and Tuning of QCL Frequency Combs via RF-Injection
(2021)2021 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)Quantum cascade laser (QCL) optical frequency combs [1] , [2] are emerging as promising sources in mid-infrared spectroscopy due to their ability to act as coherent broadband sources at room temperature with equidistant phase-locked modes. Their short sub-picosecond upper-state lifetime enables high modulation speeds of the device in the order of tens of gigahertz [3] . Since the devices are electrically driven, the intermode beating, ...Other Conference Item -
Quantum cascade laser femtosecond pulses for supercontinuum generation
(2022)OSA Technical Digest ~ Conference on Lasers and Electro-OpticsIn this work, we demonstrate the generation of 630 fs, 4.5 W pulses from a mid-infrared quantum cascade laser by gain modulation induced spectral broadening and external pulse compression. Such sources open new pathways for broadband supercontinuum generation in the mid-infrared.Other Conference Item -
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RF-Injection Controlled Quantum Cascade Lasers
(2022)OSA Technical Digest ~ Conference on Lasers and Electro-OpticsWe demonstrate the manipulation of the quantum cascade laser output state using microwave-injection. In the spectral domain, the optical bandwidth can be doubled, whereas in the time-domain, we observe narrow, approximately 1 ps wide features.Other Conference Item -
RF-Injection Controlled Quantum Cascade Lasers
(2022)Technical Digest Series ~ Optica High-brightness Sources and Light-driven Interactions Congress 2022In this work, we control the quantum cascade laser output state using microwave modulation. We demonstrate doubling of the spectral bandwidth as well as the generation of very narrow, approximately 1 ps wide features.Other Conference Item -
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Low threshold quantum cascade surface emitting lasers
(2023)Proceedings of SPIE ~ Quantum Sensing and Nano Electronics and Photonics XIXWe present low threshold quantum cascade surface emitting lasers (QCSELs) emitting at wavelengths of 4.5 micrometers or 8 micrometers. To extract the light vertically from the InP-based buried heterostructure laser a second order InGaAs/InP grating is used. Both ridge facets are formed by dry-etching followed by coating a dielectric-metal film. Due to the high reflectivity of the facets, the cavity can be shortened well below 500 micrometers ...Other Conference Item -
RF-Injection Controlled of Quantum Cascade Lasers in the Time-Domain
(2022)OSA Technical Digest ~ European Conference on Optical Communication (ECOC) 2022In this work, we demonstrate control over the time-domain state quantum cascade laser output state using microwave modulation. We demonstrate narrow, pulse-like features with a full-with at half-maximum of 558 fs when isolated, which corresponds to the expected Fourier-transform limited pulse-width.Other Conference Item