Long wavelength (15 and 23 μm) GaAs/AlGaAs quantum cascade lasers (original) (raw)
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Improved performance of GaAs-AlGaAs superlattice quantum cascade lasers beyond/spl lambda/= 13 μm
Highly improved quantum cascade lasers based on intraband transitions in a chirped AlGaAs-GaAs superlattice have been realized. Lasing in a liquid nitrogen environment with a laser wavelength centered at 13 m and with a peak optical power per facet exceeding 80 mW is achieved. A threshold current density of 8.6 kA/cm 2 at 80 K has been measured. Multimode lasing spectra ranging from 12.4 to 13.3 m and single mode spectra in a short cavity at 13 m are obtained. To improve the gain in the structure, the design of the injector is optimized. The minibands in the active region are more strongly confined beneath the conduction band edge of the barriers to decrease electron losses into the continuum. The maximum operating temperature exceeds 230 K with 0 values of 170 K. Index Terms-Environmental sensing, infrared spectroscopy, mid-infrared, semiconductor superlattices, unipolar semiconductor laser.
Improved performance of GaAs-AlGaAs superlattice quantum cascade lasers beyond /spl lambda/=13 μm
IEEE Photonics Technology Letters, 2000
Highly improved quantum cascade lasers based on intraband transitions in a chirped AlGaAs-GaAs superlattice have been realized. Lasing in a liquid nitrogen environment with a laser wavelength centered at 13 m and with a peak optical power per facet exceeding 80 mW is achieved. A threshold current density of 8.6 kA/cm 2 at 80 K has been measured. Multimode lasing spectra ranging from 12.4 to 13.3 m and single mode spectra in a short cavity at 13 m are obtained. To improve the gain in the structure, the design of the injector is optimized. The minibands in the active region are more strongly confined beneath the conduction band edge of the barriers to decrease electron losses into the continuum. The maximum operating temperature exceeds 230 K with 0 values of 170 K. Index Terms-Environmental sensing, infrared spectroscopy, mid-infrared, semiconductor superlattices, unipolar semiconductor laser.
GaAs/AlGaAs (~9.4 μm) quantum cascade lasers operating at 260 K
Bulletin of the Polish Academy of Sciences: Technical Sciences, 2000
The fabrication of Quantum Cascade Lasers (QCLs) emitting at ∼9.4 µm is reported. The devices operated in pulsed mode at up to 260 K. The peak powers recorded in 77 K were over 1 W, and the slope efficiency η ≈ 0.5-0.6 W/A per uncoated facet. This has been achieved by the use of GaAs/Al0.45Ga0.55As heterostructure, with 3QW anticrossed-diagonal design originally proposed by Page et al. . Double plasmon planar confinement with Al-free waveguide has been used to minimize absorption losses. The double trench lasers were fabricated using standard processing technology, i.e., wet etching and Si3N4 for electrical insulation. The QCL structures have been grown by Molecular Beam Epitaxy (MBE), with Riber Compact 21T reactor. The stringent requirements -placed particularly on the epitaxial technology -and the influence of technological conditions on the device structure properties are presented and discussed in depth.
GaAs Quantum Cascade Lasers: Fundamentals and Performance
Les lasers : applications aux technologies de l'information et au traitement des matériaux, 2002
Quantum engineering of the electronic energy levels and tailoring of the wavefunctions in GaAs/Al x Ga 1−x As heterostructures allows to obtain the correct matrix elements and scattering rates which enable laser action between subbands. This article reviews the state-of-the-art of GaAs based quantum cascade lasers. These new light sources operate, with peak power in excess of 1 W at 77 K, in the 8-13 µm wavelength region, greatly extending the wavelength range of GaAs optoelectronic technology. Waveguides are based on an Al-free design with an appropriate doping profile which allows optical confinement, low losses and optimal heat dissipation. Finally, new active region designs aiming to improve the laser temperature dependence are discussed. Recent results on these devices confirm that the ratio between the conduction band discontinuity and the photon energy (∆E c /E laser) is the dominant parameter controlling their thermal characteristic. The maximum operating temperature of these devices is 280 K for lasers with emission wavelength at ∼11 µm.
Room temperature AlGaAs/GaAs quantum cascade lasers
Photonics Letters of Poland, 2011
The room temperature (293K), pulsed mode operation of a GaAs-based quantum cascade laser (QCL) is reported. This has been achieved by the use of GaAs/Al 0.45 Ga 0.55 As heterostructure. Its design follows an "anticrossed-diagonal" scheme. The QCL structures were grown by MBE in a Riber Compact 21T reactor. The double trench lasers were fabricated using standard processing technology, i.e., wet etching and Si 3 N 4 for electrical insulation. Double plasmon confinement with Al-free waveguide has been used to minimize absorption losses. High operating temperatures have been achieved by careful optimization of growth technology and using metallic high reflectivity facet coating on the back facet of the laser.
Intersubband and interminiband GaAs/AlGaAs quantum cascade lasers
Physica E: Low-dimensional Systems and Nanostructures, 2000
Electrically pumped injection lasers based on the GaAs=AlGaAs material system are investigated. Intersubband transitions in coupled quantum wells and intraband transitions in a ÿnite superlattice are used to demonstrate lasing. The laser emission wavelength is 10 m for the intersubband lasers and 12:9 m for the laser structure having a ÿnite superlattice as an active cell. Utilizing ridge waveguide laser bars at a heat-sink temperature of 10 K, peak optical powers of the intersubband quantum cascade lasers exceed 300 mW (interminiband: 100 mW). The maximum operating temperature is 160 K (interminiband: 50 K). Cylindrical micro-cavities show single-mode behavior with a side mode suppression ratio better than 25 dB for both kinds of lasers.
Semiconductor …, 2004
Using microprobe photoluminescence we measured the electronic and lattice temperatures in operating quantum cascade lasers having similar chirped-superlattice active regions but different (GaAs/AlAs or GaAs/Al 0.45 Ga 0.55 As) conduction band discontinuities. Our results demonstrate the establishment of a thermalized hot-electron distribution. Coupling between the electronic ensemble and the lattice increases with the band-offset and influences the optical characteristics of the devices.
High performance single mode GaAs quantum cascade lasers
We report on the realization of distributed feedback quantum cascade lasers in the AlGaAs=GaAs material system. Strong coupling is achieved by the use of a metalized surface relief grating, allowing the realization of short lasers. Continuous wave operation was achieved for an AlAs=GaAs chirped superlattice laser with an emission wavelength of 11:8 m. The used double plasmon enhanced optical waveguide consists only of the binary material GaAs and not of a ternary compound which results in a small thermal resistance. Further, the emission wavelength of the distributed feedback laser is continuously tunable according to the temperature dependence of the refractive index. Additionally, we want to report about pulsed single mode operation up to 335 K for a laser material, where Al0:45Ga0:55As is used for the barriers and GaAs for the wells. The emission wavelength is 9:5 m and the optical peak power in pulsed mode operation from one facet of the distributed feedback laser is 0:3 W at a temperature of 0 • C. ? 2002 Elsevier Science B.V. All rights reserved.
Quantum cascade lasers at ∼ 16 μ m wavelength based on GaAs / AlGaAs
2018
Mid-infrared (3-30 μm) quantum-cascade (QC) lasers are usually designed and realized in InGaAs/AlInAs on an InP substrate. InP is a commonly-used substrate for semiconductor lasers because of its compatibility with InGaAs and AlInAs for tuning the depth of quantum wells in quantum-cascade lasers and its utility as a waveguide cladding material. However, its two-phonon resonance energy corresponds almost exactly to the energy of 16 μm photons, and so makes InP-based 16-μm QC lasers inefficient and low performing. 16 μm lasers are important for BTEX or UF6 sensors. GaAs is the next best substrate for such a laser. In this paper, we design a new 16-μm GaAs-based QC laser and provide the background understanding for QC lasers in general. The active and injector region period length is Lp = 520.4 Å. The figure of merit for the differential gain coefficient is 1.32, which is low, but it exhibits carrier inversion and would lase, making it a good preliminary design upon which to make modif...
Development of (λ ∼ 9.4μm) GaAs-based quantum cascade lasers operating at the room temperature
NATO Science for Peace and Security Series B: Physics and Biophysics, 2011
The development of (λ ∼ 9.4 µm) GaAs-based quantum cascade lasers (QCLs) operating at the room temperature is reported. The laser design followed an "anticrossed-diagonal" scheme of Page et al. . The QCL GaAs/Al 0.45 Ga 0.55 As heterostructures were grown by solid source (SS) MBE. The double trench lasers were fabricated using wet etching and Si 3 N 4 for electrical insulation. Double plasmon confinement with Al-free waveguide has been used to minimize absorption losses. Optical and electrical properties of resulting devices are presented and discussed.