Paper
8 April 2004 Low-threshold superlattice quantum cascade laser emitting at λ = 103 μm and operating up to 70 K in continuous wave
Jesse Alton, Stefano Barbieri, Harvey E. Beere, John Fowler, Edmund H. Linfield, David A. Ritchie
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Abstract
We demonstrate the operation of a superlattice GaAs/AlGaAs quantum cascade laser emitting at λ = 103 μm. The maximum operating temperature is 95K in pulsed mode and 70K in continuous wave. At 4K, we measured a peak output power in the tens of mW range and a threshold current density of 110 A/cm2 (300 A/cm2 at 90K). We attribute this excellent performance to a low ratio between the lower and upper state lifetimes, as well as to a low leakage current. These characteristics are highlighted by a pronounced decrease of the differential resistance at threshold and by the fact that the slope efficiency remains constant up to approximately 70K. At any temperature, we observe an abrupt decrease of the output power at the breaking of miniband alignment, corresponding to a strong negative differential resistance feature in the current/voltage characteristics. Ultimately, this effect limits the operation of the device at high temperatures. By comparing this laser with a previous design, we will outline the importance of (i) having a diagonal rather than vertical laser transition in real space, and (ii) avoiding possible intersubband re-absorption of the emitted radiation.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jesse Alton, Stefano Barbieri, Harvey E. Beere, John Fowler, Edmund H. Linfield, and David A. Ritchie "Low-threshold superlattice quantum cascade laser emitting at λ = 103 μm and operating up to 70 K in continuous wave", Proc. SPIE 5354, Terahertz and Gigahertz Electronics and Photonics III, (8 April 2004); https://doi.org/10.1117/12.537784
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Cited by 7 scholarly publications.
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KEYWORDS
Continuous wave operation

Quantum cascade lasers

Superlattices

Pulsed laser operation

Resistance

Laser damage threshold

Solids

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