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ABSTRACT: The performances of Ga As / Al <sub>0.15</sub> Ga <sub>0.85</sub> As terahertz quantum cascade lasers based on a bound-to-continuum transition are investigated as a function of injector doping. A linear dependence between threshold current and doping is found and agrees with the expected increase of waveguide losses due to free carrier absorption.
Journal of Applied Physics 09/2006; · 2.17 Impact Factor
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ABSTRACT: Intersubband transitions and magnetic quantization are exploited to realize an extremely low threshold quantum cascade laser emitting at λ ≃ 160 μm. Non‐radiative Auger processes are efficiently quenched when the system reaches the condition of strong in‐plane confinement, allowing laser action with threshold current densities as low as 1 A/cm2 at 4.2 K at 13 T and pulsed operating temperatures of 65 K. Characteristic features in light emission and transport are recognized as signatures of single and two‐electron scattering processes between Landau levels. © 2005 American Institute of Physics
AIP Conference Proceedings. 06/2005; 772(1):1573-1574.
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ABSTRACT: We have assembled a single-frequency imaging system at 3.4 THz with a quantum-cascade laser. Images of electronic and biological applications are demonstrated. We operate the laser with a peak output power of 2.5 mW at a 7% duty cycle and a 22 K operating temperature. The minimum spot size is 340 microm. The signal is detected with a single-element deuterated triglycine sulfate detector, and images are captured by scanning of the sample.
Applied Optics 02/2005; 44(1):121-5. · 1.41 Impact Factor
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ABSTRACT: We report high power quantum cascade lasers operating above liquid nitrogen temperature at λ≃87 and 130 μ m based on a bound-to-continuum transition. For λ≃87 μ m , 56 mW peak power in pulsed operation and 50 mW continuous wave operation at 10 K are demonstrated. At λ≃130 μ m , a peak power of 50 mW was achieved and devices operated in continuous wave reached a maximum temperature of 53 K with an optical power of 11.5 mW at T=10 K . Lifetimes are extracted from the scaling of the transport and laser parameters as a function of size using a simple rate equation model.
Applied Physics Letters 12/2004; · 3.84 Impact Factor
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ABSTRACT: Recent developments in terahertz quantum cascade lasers are reviewed. Structures operating from a wavelength of lambda = 66 microm down to lambda = 87 microm are demonstrated. These devices used either a three-quantum-well chirped-superlattice active region or an active region based on a bound-to-continuum transition. The comparison between structures grown in a waveguide based on a single interface plasmon and a buried contact and (non-lasing) structures using a double plasmon waveguide demonstrates the importance of waveguide design on the operation of such devices. Continuous-wave operation up to a maximum temperature of 55 K with up to 15 mW output power at 10 K was demonstrated.
Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences 03/2004; 362(1815):215-29; discussion 229-31. · 2.77 Impact Factor
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Diane C Larrabee,
Giti A Khodaparast,
Frank K Tittel,
Jun Kono,
Giacomo Scalari, Lassaad Ajili,
Jerome Faist,
Harvey Beere,
Giles Davies,
Edmund Linfield,
David Ritchie,
Yoji Nakajima,
Masato Nakai,
Shigehiko Sasa,
Masataka Inoue,
Seokjae Chung,
Michael B Santos
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ABSTRACT: Quantum-cascade lasers operating at 4.7, 3.5, and 2.3 THz have been used to achieve cyclotron resonance in InAs and InSb quantum wells from liquid-helium temperatures to room temperature. This represents one of the first spectroscopic applications of terahertz quantum-cascade lasers. Results show that these compact lasers are convenient and reliable sources with adequate power and stability for this type of far-infrared magneto-optical study of solids. Their compactness promises interesting future applications in solid-state spectroscopy.
Optics Letters 02/2004; 29(1):122-4. · 3.40 Impact Factor
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ABSTRACT: A quantum-cascade laser operating at λ=66 μ m is demonstrated. It consists of a three-quantum-well chirped-superlattice active region embedded in a waveguide based on a single interface plasmon and a buried contact. A threshold current density of 210 A/cm <sup>2</sup> at T=12 K , a maximum peak optical power of 4 mW, and operation up to T=44 K are achieved in a 2.7 mm long device with a high reflectivity backfacet coating. © 2002 American Institute of Physics.
Applied Physics Letters 09/2002; · 3.84 Impact Factor
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ABSTRACT: Graded superlattice quantum cascade lasers have shown high operation performance in the mid-infrared. A similar design has been used for terahertz intersubband emission. Narrow band ((= 3 meV) waveguide emission was observed at an energy of 18:8 meV. The energy spectrum was conÿrmed by magneto-transport measurements. ? 2002 Elsevier Science B.V. All rights reserved.
Physica E. 01/2002; 13:854-857.
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ABSTRACT: Graded superlattice quantum cascade lasers have shown high operation performance in the mid-infrared. A similar design has been used for terahertz intersubband emission. Narrow band () waveguide emission was observed at an energy of . The energy spectrum was confirmed by magneto-transport measurements.
Physica E: Low-dimensional Systems and Nanostructures.
