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An electrical tuning method for terahertz quantum-cascade lasers (QCLs) is developed based on detuned intersubband absorption in coupled metallic microcavities, which works even at high operating temperatures. Continuous 4 GHz tuning for a single-mode narrow-beam 3.57 THz QCL operating at ∼ 50 K in a Stirling cryocooler is demonstrated.
A broadband bidirectional terahertz quantum-cascade laser operating up to 147K and emitting in the frequency range of 3.1–3.7THz is demonstrated. A three-well GaAs/AlGaAs design with 10%Al barriers is shown to be optimum for bidirectional lasing.
A distributed antenna-coupling scheme for THz quantum cascade lasers is introduced. Single-mode emission in a narrow beam pattern, with an order of magnitude increase in output power is predicted compared to previous distributed-feedback schemes.
Terahertz quantum cascade lasers (QCLs) emit radiation due to intersubband optical transitions in semiconductor superlattices that could be engineered by design. Among a variety of possible design schemes, we have pursued designs that utilize strong electron-phonon interaction in the semiconductor as a means to establish population inversion for optical gain. This report describes the recent progress...
We report a novel tuning mechanism based on a “wire-laser” with subwavelength transverse dimensions(w≪λ). By manipulating the waveguided mode propagating outside the cavity, frequency tuning of ∼137GHz (3.6%) is demonstrated from a single-laser device at ∼3.8THz.
The maximum operating temperature of previously reported terahertz quantum-cascade lasers (QCLs) has empirically been limited to a value of ~ ħω/kB. Here, we report a new design scheme for terahertz QCLs and achieve 163-K operation for a 1.8-THz QCL, which is a factor of 1.9 larger than ħω/kB.
Terahertz quantum-cascade lasers are based on intersubband optical transitions that could be “engineered”. Operation above 160 K has been demonstrated for frequencies ranging from 1.8-4.4 THz. This talk reviews their recent progress, design aspects and future challenges.
We report the demonstration of terahertz QCLs based on a two-phonon depopulation scheme, intended to improve the high-temperature performance, and also the demonstration of QCLs emitting 250 mW in pulsed mode at 4.3 THz
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