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Université de Neuchâtel

Measurement of the linewidth enhancement factor of singlemode room temperature continuous wave quantum cascade lasers

Aellen, Thierry ; Aebi, Philipp (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2008.

The invention of the laser source in 1960 has led to a wide range of applications showing a widespread impact in every aspect of our today life, including for example hospital, factory or simply at home. In particular, recent developments originating from the compact, highly efficient and common semiconductor lasers that are simply supplied by an electrical current. The diode coherent light...

Université de Neuchâtel

Continuous Wave Operation of a Mid-Infrared Semiconductor Laser at Room Temperature

Beck, Mattias ; Hofstetter, Daniel ; Aellen, Thierry ; Faist, Jérôme ; Oesterle, Ursula ; Ilegems, Marc ; Gini, Emilio ; Melchior, Hans

In: Science, 2002, vol. 295, no. 5553, p. 301-305

Continuous wave operation of quantum cascade lasers is reported up to a temperature of 312 kelvin. The devices were fabricated as buried heterostructure lasers with high-reflection coatings on both laser facets, resulting in continuous wave operation with optical output power ranging from 17 milliwatts at 292 kelvin to 3 milliwatts at 312 kelvin, at an emission wavelength of 9.1 micrometers. The...

Université de Neuchâtel

Continuous-wave operation of quantum cascade laser emitting near 5.6 µm

Yarekha, D. A. ; Beck, Mattias ; Blaser, Stéphane ; Aellen, Thierry ; Gini Emilio ; Hofstetter, Daniel ; Faist, Jérôme

In: Electronics Letters, 2003, vol. 39, no. 15, p. 1123-1125

Buried heterostructure quantum cascade lasers emitting at 5.64 µm are presented. Continuous-wave (CW) operation has been achieved at –30°C for junction down mounted devices with both facets coated. A 750 µm-long laser exhibited 3 mW of CW power with a threshold current density of 5.4 kA/cm2.

Université de Neuchâtel

Continuous wave operation of quantum cascade lasers

Beck, Mattias ; Hofstetter, Daniel ; Aellen, Thierry ; Blaser, Stéphane ; Faist, Jérôme ; Oesterle, Ursula ; Gini Emilio

In: Journal of Crystal Growth, 2003, vol. 251, no. 1-4, p. 697-700

Continuous wave (CW) operation of quantum cascade lasers is reported up to temperatures of 312 K. The devices were fabricated as buried heterostructure lasers and episide-down mounted for improved heat dissipation. Fabry–Perot lasers emitted 17 mW of continuous optical power at 292 K and still 3 mW at 311 K at λ=9.12 μm. Distributed feedback quantum cascade lasers showed CW single-mode...

Université de Neuchâtel

Spectroscopic study of the ν1 band of SO2 using a continuous-wave DFB QCL at 9.1 µm

Joly, L. ; Zéninari, V. ; Parvitte, B. ; Weidmann, D. ; Courtois, D. ; Bonetti, Yargo ; Aellen, Thierry ; Beck, Mattias ; Faist, Jérôme ; Hofstetter, Daniel

In: Applied Physics B: Lasers and Optics, 2004, vol. 77, no. 6-7, p. 703-706

We report results of spectroscopic measurements with a continuous-wave distributed-feedback quantum-cascade laser (DFB QCL). Line intensities and self-broadening coefficients were measured in the ν1 band of SO2 between 1088 and 1090 cm-1. The self-broadening coefficients in this paper confirm the typical decrease of νself with increasing rotational...

Université de Neuchâtel

Mid-infrared trace-gas sensing with a quasi- continuous-wave Peltier-cooled distributed feedback quantum cascade laser

Weidmann, D. ; Tittel, F. K. ; Aellen, Thierry ; Beck, Mattias ; Hofstetter, Daniel ; Faist, Jérôme ; Blaser, Stéphane

In: Applied Physics B: Lasers and Optics, 2004, vol. 79, no. 7, p. 907-913

A recently developed distributed feedback quantum cascade laser (QCL) capable of thermoelectric-cooled (TEC) continuous-wave (cw) operation and emitting at ~9 μm is used to perform laser chemical sensing by tunable infrared spectroscopy. A quasi-continuous-wave mode of operation relying on long current pulses (~5 Hz, ~50% duty cycle) is utilized rather than pure cw operation in order to extend...

Université de Neuchâtel

Free-running 9.1-μm distributed-feedback quantum cascade laser linewidth measurement by heterodyning with a C18O2 laser

Weidmann, D. ; Joly, L. ; Parpillon, V. ; Courtois, D. ; Bonetti, Yargo ; Aellen, Thierry ; Beck, Mattias ; Faist, Jérôme ; Hofstetter, Daniel

In: Optics Letters, 2003, vol. 28, no. 9, p. 704-706

We report spectral linewidth measurements of a 9.1-μm distributed-feedback quantum cascade laser (QCL). The free-running QCL beam was mixed with a waveguide isotopic C18O2 laser onto a high-speed HgCdTe photomixer, and beat notes were recorded from a radio-frequency spectral analyzer. Beating was performed at two operating conditions, first near the QCL laser...

Université de Neuchâtel

Microfluidic tuning of distributed feedback quantum cascade lasers

Diehl, Laurent ; Lee, Benjamin G. ; Behroozi, Peter ; Loncar, Marko ; Belkin, Mikhail ; Capasso, Federico ; Aellen, Thierry ; Hofstetter, Daniel ; Beck, Mattias ; Faist, Jérôme

In: Optics Express, 2006, vol. 14, no. 24, p. 11660-11667

In this Letter, we report the tuning of the emission wavelength of a single mode distributed feedback quantum cascade laser by modifying the mode effective refractive index using fluids. A fabrication procedure to encapsulate the devices in polymers for microfluidic delivery is also presented. The integration of microfluidics with semiconductor laser (optofluidics) is promising for new compact...

Université de Neuchâtel

Bound-to-continuum and two-phonon resonance, quantum-cascade lasers for high duty cycle, high-temperature operation

Faist, Jérôme ; Hofstetter, Daniel ; Beck, Mattias ; Aellen, Thierry ; Rochat, Michel ; Blaser, Stéphane

In: Journal of Quantum Electronics (IEEE), 2002, vol. 38, no. 6, p. 533-546

Recent advances in quantum-cascade (QC) laser active-region design are reviewed. Based on a rate equation model of the active region, we show why new gain regions. based on a two-phonon resonance or a bound-to-continuum transition exhibit significantly better performance than the traditional design based on a three-quantum-well active region. Threshold current densities as low as 3...

Université de Neuchâtel

High-frequency modulation of a quantum-cascade laser using a monolithically integrated intracavity modulator

Hofstetter, Daniel ; Beck, Mattias ; Aellen, Thierry ; Blaser, Stéphane

In: Photonics Technology Letters (IEEE), 2003, vol. 15, no. 8, p. 1044-1046

We report a quantum-cascade laser monolithically integrated with an intracavity modulator which could be operated up to 1 GHz. In contrast to earlier approaches, where the radio frequency (RF) modulation signal was supplied to the entire cavity length of the laser structure, we drive only a relatively small 375-/spl mu/m-long section of the cavity. At the same time, a quasi-continuous-wave signal...