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High-performance THz QCL frequency combs
(2020)Proceedings of SPIE ~ Quantum Sensing and Nano Electronics and Photonics XVIIA broadband, Cu-Cu THz quantum cascade laser is presented. The device shows an 50% improved dynamical range and doubled peak power in pulsed compared to Au-Au devices. The pulsed maximum lasing temperature was increased from 105 K to 133 K. In CW similar bandwidths for Cu-Cu and Au-Au devices are observed with an increased temperature performance. At 77 K the emitted power of the device is reduced by 57% compared to 30 K. At this temperature ...Other Conference Item -
THz Intersubband Emitter based on Silicon
(2021)2021 27th International Semiconductor Laser Conference (ISLC)We present THz quantum cascade emitters realized on a Si substrate. The emission centered at 3.4 and 4.9 THz originates from L-valley transitions in strain-compensated n-type Ge/SiGe heterostructures. This is an important step towards the realization of Si-based THz quantum cascade lasers.Other Conference Item -
Terahertz intersubband electroluminescence from n-type germanium quantum wells
(2021)2021 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)The Quantum Cascade Laser (QCL) has been demonstrated in polar III-V semiconductor materials employing transitions between conduction band states [1] . Harnessing intersubband transitions allows lasing at mid-infrared and far-infrared wavelengths. Buried InGaAs/InAlAs QCLs unlocked the mid-infrared application space, because they are operational at room-temperature and in continuous wave [2] . However, THz QCLs remain limited up to 250 K ...Other Conference Item -
THz Quantum Cascade Laser Frequency Comb based on a Y-coupled Planarized Waveguide
(2021)2021 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)Terahertz (THz) quantum cascade lasers (QCLs) can operate as frequency combs [1] and dual combs [2] , making them very appealing for spectroscopy and metrology applications. Recently, Y-split THz QCLs were investigated in the context of tunable single mode operation [3] . Here, we present a Y-coupled double metal planarized waveguide geometry to study broadband phase locking and frequency comb formation.Other Conference Item -
Ultra-low Threshold Quantum Cascade Laser
(2021)2021 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)Quantum cascade lasers (QCLs) are widely used in the mid-infrared region for spectroscopic and gas-sensing applications. Due to the high operating voltage and typically Watt-level input power, bulky cooling systems are generally needed for driving a QCL at continuous-wave operation, which limit QCL applications on portable platforms. One approach for reducing the threshold dissipation power of a QCL is the combination of small volume ...Other Conference Item -
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Planarized waveguides for high-performance THz quantum cascade laser frequency
(2022)Proceedings of SPIE ~ Quantum Sensing and Nano Electronics and Photonics XVIIIWe present a planarized double metal waveguide THz quantum cascade laser, where the top contact metallization extends beyond the active region, above the surrounding low-loss BCB polymer. Placing wire bonds over the BCB-covered area enables the fabrication of extremely narrow waveguide dimensions with reduced power dissipation. Compared to a standard double metal waveguide, improvements in waveguide losses, dispersion, RF and thermal ...Other Conference Item -
Field-enhancing tapered planarized waveguides for THz quantum cascade laser frequency combs
(2022)EPJ Web of Conferences ~ EOS Annual Meeting (EOSAM 2022)We present a new planarized waveguide geometry for THz quantum cascade laser frequency combs with improved waveguide losses, RF and thermal dissipation properties. Ridge devices display broadband free-running comb states, and the THz emission can be further broadened by RF injection. Tapered waveguide devices feature a strong field-enhancement effect, which results in an improved comb performance. This includes free-running comb states ...Other Conference Item -
Characterization and analysis of a symmetry-breaking THz chiral metamaterial
(2022)QUANTUMatter 2022 Abstract BookOther Conference Item -