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We provide a simple explanation for why laser media with distributed loss should have a sublinear output power characteristic. This understanding clarifies the role of long-range spatial hole burning in reducing the efficiency of semiconductor lasers, and is essential for optimizing power output.
We present the first realization of a single-mode surface-emitting quantum cascade laser array. The ten lasers operate over a bandwidth of 175 cm−1 between wavelengths of 8 and 10 μm and show similar pumping characteristics. The device is compatible with milliwatt continuous wave operation, which makes it suitable for spectroscopic applications.
We demonstrate the first long-wave, room temperature II-VI materials based Quantum Cascade emitter around 7.2 μm. At 80 K, a device differential resistance of 2.6 Ω and a narrow electroluminescent width of 16% was obtained.
MIR spectroscopy using QCL allows sensitive, selective and fast gas detection. This is illustrated by many environmental and industrial applications. Recent developments show significant advances towards portable, high-sensitivity sensors for multiple components.
We demonstrated the feasibility of multicomponent trace gas sensing using a tunable sampled-grating distributed Bragg reflector QCL. We have achieved continuous fine tuning over 10 cm−1 to retrieve N2O, H2O and CO.
Mid-infrared VECSEL tunable over 50 cm−1 is employed to measure trace gas concentrations of acetone in human breath. A detection limit of 25 ppb is demonstrated without any sample preparation.
We report on design, fabrication and investigation of a buried heterostructure photonic crystal quantum cascade laser operating in the mid-IR (8.5μm) at room temperature, leading to single mode emission on a 600μm by 600μm mesa.
We measure and analyze mixtures of trace gases at ppb-ppm levels using an external cavity quantum cascade laser sensor with a 1-second response time. Accurate spectral fits are obtained in the presence of overlapping spectra.
We report a sampled grating quantum cascade laser with excellent tuning stability over the full tuning range (106 cm-1). Spatial hole burning and facet reflections can cause unpredictable mode jumping. We present a stabilization method.
Scanning voltage microscopy results clearly show that the formation of electric field domains is responsible for the missing of lasing operation in a resonant-phonon based terahertz quantum cascade laser with a highly diagonal transition.
Since the first demonstration of the quantum cascade laser (QCL) in 1994, three main material families have been used. Each of these three materials best suits a specific wavelength range, due to differences in electronic effective mass, conduction band offset and index of refraction. The material of choice for mid-infrared (mid-IR) applications is InGaAs/AlInAs, with excellent performances demonstrated...
An integrated mid-infrared sensor consisting of an array of DFB lasers and detectors built from a bi-functional quantum cascade structure is demonstrated. The different frequencies enable the identification of the chemicals in a liquid mixture.
A next-generation bistatic, open-path sensor is currently in development that utilizes a Quantum cascade laser array for the source in order to achieve methane and nitrous oxide detection over path lengths exceeding 100 m.
Mid-IR interband cascade lasers will be reviewed. Advantages include 3–6 μm spectral coverage, wallplug efficiency up to 18% when operated in cw mode at ambient temperature, and ultra-low threshold drive power.
A terahertz quantum cascade laser is injection seeded with narrow-band seed pulses generated from a periodically poled lithium niobate crystal. The spectral emission of the quantum cascade laser is controlled by the seed spectra.
We report the first fully fiber-interfaced heterodyne system for time-resolved spectral characterization of THz quantum cascade lasers. By exploiting the bias probe rise time we study the current dependent mode tuning with 50ns temporal resolution.
We provide the first experimental demonstration of room temperature far-infrared lab-on-chip chemical sensing via monolithic integration of quantum cascade laser, quantum cascade detector and dielectric waveguides at the long infrared wavelength of 9.5μm.
Electroluminescence spanning 3.3μm to 12.5μm and with a full width half maximum of 4μm is achieved using a single stack quantum cascade gain medium. The free-running laser emits from 7.4μm to 12.1μm.
An external cavity quantum cascade laser based on Fabry-Pérot etalon design is demonstrated for the first time. The Fabry-Pérot reflector was adjusted to produce single mode emission across the whole gain region.
A compact QCL-based open-path NO sensor is developed at 5.26 μm for high sensitivity and fast response. Combined with existing NH3 and N2O sensors, this system measures primary emissions of reactive nitrogen to the atmosphere.
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