O. Cathabard

Quantum cascade lasers emitting near 2.6 μm

Quantum cascade lasers (QCLs) emitting at wavelengths as short as 2.63–2.65u2002μm are demonstrated. The InAs/AlSb QCL design was optimized to weaken carrier leakage into the L-valley by reducing coupling between the active InAs quantum wells. The lasers with HR-coated facets operated up to 175 K.

InAs∕AlSb quantum cascade lasers emitting below 3μm

Quantum cascade lasers emitting below 3μm are demonstrated. The lasers based on the InAs∕AlSb material system emit at 2.95–2.97μm in pulsed mode with threshold current densities near 3kA∕cm2 at 84K and operate up to room temperature. No degradation has been observed in laser performances compared with InAs∕AlSb quantum cascade lasers emitting at 3.14–3.35μm. The obtained results show no influence of the L valley in InAs on operation of these short wavelength quantum cascade lasers.

InAs∕AlSb quantum cascade lasers emitting at 2.75–2.97μm

Quantum cascade lasers emitting at wavelengths as short as 2.75μm at 80K and 2.97μm near room temperature are demonstrated. Despite the small band gap of InAs, the laser performances are not affected by interband absorption. No effect of the L valley in InAs on quantum cascade laser performances is observed at 80K in these devices.

High temperature operation of λ≈3.3μm quantum cascade lasers

We report quantum cascade lasers emitting at a wavelength near 3.3μm up to a temperature of 400K in pulsed mode. A fine tuning of the InAs∕AlSb active region design allowed to maintain efficient electron injection and to reduce thermal backfilling at high temperatures. The threshold current density is 3kA∕cm2 at 300K with characteristic temperature T0 of 175K. The lasers emitted up to 1W peak power in a single lateral mode at room temperature.

Very short wavelength (λ=3.1–3.3μm) quantum cascade lasers

Quantum cascade lasers emitting at wavelengths as short as 3.1–3.3 m are reported. Such high intersubband emission energies up to 400 meV have been obtained thanks to the high conduction band offset of the InAs/AlSb material system. The structures, grown by molecular beam epitaxy on InAs substrates, are based on the bound-to-continuum design and use a low loss plasmon enhanced waveguide consisting of n+-InAs cladding layers with InAs/AlSb superlattice spacers surrounding the active zone. The lasers exhibit threshold current densities close to 3 kA/cm2 at 83 K and operate in pulsed mode up to 240 K.