High power terahertz quantum cascade lasers with symmetric wafer bonded active regions

Brandstetter, Markus; Deutsch, C.; Krall, Michael; Detz, Hermann; MacFarland, Donald; Zederbauer, Tobias; Andrews, A. M.; Schrenk, W.; Strasser, G.; Unterrainer, K.

doi:10.1063/1.4826943

Cited by 80 publications

(47 citation statements)

References 21 publications

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“…Since the first demonstration in 2002, 3 THz QCLs have witnessed a rapid development. Till date, the frequency ranges from 1.2 to 5.0 THz 4,5 and the highest output power in pulsed wave (PW) mode achieves more than 1 W. 6,7 However, the output power in continuous wave (CW) mode is still limited to 138 mW since 2006. 8 This is an impediment toward many important applications in spectroscopy, imaging, remote sensing, etc.…”

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confidence: 99%

High-power terahertz quantum cascade lasers with ∼0.23 W in continuous wave mode

et al. 2016

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Terahertz quantum cascade lasers with a record output power up to ∼0.23 W in continuous wave mode were obtained. We show that the optimal 2.9-mm-long device operating at 3.11 THz has a low threshold current density of 270 A/cm2 at ∼15 K. The maximum operating temperature arrived at ∼65 K in continuous wave mode and the internal quantum efficiencies decreased from 0.53 to 0.19 for the devices with different cavity lengths. By using one convex lens with the effective focal length of 13 mm, the beam profile was collimated to be a quasi Gaussian distribution.

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confidence: 99%

High-power terahertz quantum cascade lasers with ∼0.23 W in continuous wave mode

et al. 2016

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“…In terms of size, output power, and efficiency, THz quantum cascade lasers (QCLs) 2,3 are the devices of choice to generate such radiation. These electrically pumped semiconductor lasers are capable of delivering watt-level output power 4,5 and reach maximum operating temperatures up to 200 K. 6 Dependent on the specific application, it is essential to use single mode lasers with high spectral purity, e.g. for local oscillators in heterodyne receivers, 7 whereas for other applications, THz QCLs with broadband gain media are highly desirable.…”

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confidence: 99%

Spectral gain profile of a multi-stack terahertz quantum cascade laser

Bachmann

Rösch

Deutsch

et al. 2014

Applied Physics Letters

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The spectral gain of a multi-stack terahertz quantum cascade laser, composed of three active regions with emission frequencies centered at 2.3, 2.7, and 3.0 THz, is studied as a function of driving current and temperature using terahertz time-domain spectroscopy. The optical gain associated with the particular quantum cascade stacks clamps at different driving currents and saturates to different values. We attribute these observations to varying pumping efficiencies of the respective upper laser states and to frequency dependent optical losses. The multi-stack active region exhibits a spectral gain full width at half-maximum of 1.1 THz. Bandwidth and spectral position of the measured gain match with the broadband laser emission. As the laser action ceases with increasing operating temperature, the gain at the dominant lasing frequency of 2.65 THz degrades sharply.

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“…As a consequence, an important activity in this field is dedicated to developing sources such as photoconductive devices [8,9], quantum cascade lasers [10] or exploring new schemes for THz generation like intracavity difference-frequency generation in mid-infrared quantum cascade lasers [11]. In parallel, important effort is dedicated to the study of new physical properties within novel materials [12,13].…”

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Terahertz Generation by Dynamical Photon Drag Effect in Graphene Excited by Femtosecond Optical Pulses

et al. 2014

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Nonlinear couplings between photons and electrons in new materials give rise to a wealth of interesting nonlinear phenomena [1]. This includes frequency mixing, optical rectification or nonlinear current generation, which are of particular interest for generating radiation in spectral regions that are difficult to access, such as the terahertz gap. Owing to its specific linear dispersion and high electron mobility at room temperature, graphene is particularly attractive for realizing strong nonlinear effects [2]. However, since graphene is a centrosymmetric material, second-order nonlinearities a priori cancel, which imposes to rely on less attractive third-order nonlinearities [3]. It was nevertheless recently demonstrated that dc-second-order nonlinear currents [4] as well as ultrafast ac-currents [5] can be generated in graphene under optical excitation. The asymmetry is introduced by the excitation at oblique incidence, resulting in the transfer of photon momentum to the electron system, known as the

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High power terahertz quantum cascade lasers with symmetric wafer bonded active regions

Cited by 80 publications

References 21 publications

High-power terahertz quantum cascade lasers with ∼0.23 W in continuous wave mode

High-power terahertz quantum cascade lasers with ∼0.23 W in continuous wave mode

Spectral gain profile of a multi-stack terahertz quantum cascade laser

Terahertz Generation by Dynamical Photon Drag Effect in Graphene Excited by Femtosecond Optical Pulses

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