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Optically driven electron turnstile based on self-assembled semiconductor quantum dots
(2014)8th International Conference on Quantum Dots : May 11-16, 2014. Palazzo dei Congressi, Pisa, ItalyOther Conference Item -
Terascope: Portable real-time terahertz imaging using quantum cascade lasers
(2012)Other Conference Item -
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 -
Femtosecond pulses from a mid-infrared quantum cascade laser
(2021)2021 27th International Semiconductor Laser Conference (ISLC)We report on the generation of near-transform-limited femtosecond pulses from a mid-infrared quantum cascade laser by external pulse compression. The temporal nature of these pulses is assessed by means of a novel optical sampling method, coherent beatnote interferometry and interferometric autocorrelation.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 -
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 -
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 -
Spectra Characterization of Ring Quantum Cascade lasers
(2021)2021 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)The quantum cascade laser (QCL) based ring structures are becoming hot research areas for laser beam control [1] and mode-locking applications [2] . Recently, with the strong nonlinearity of active region, mid-infrared frequency comb based on ring QCLs have been demonstrated [3] , [4] , showing great potential of pulse generation without using active mode-locking scheme. In this work, we report the development of mid-infrared frequency ...Other Conference Item