Stabilization, injection and control of quantum cascade lasers, and their application to chemical sensing in the infrared

Taubman, Matthew S.; Myers, Tanya L.; Cannon, Bret D.; Williams, Richard M.

doi:10.1016/j.saa.2003.12.057

Cited by 121 publications

(55 citation statements)

References 32 publications

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“…Nevertheless, considering the narrow ro-vibrational transitions in small gas molecules, a range of new measurement approaches expanding on direct absorption spectroscopy have been demonstrated to feature important advantages in terms of ruggedness as well as sensitivity [13,14]. Some of these novel approaches exploit molecular dispersion, rather than absorption, to decouple the recorded quantity (phase or frequency) from the laser intensity [15,16].…”

Section: Introductionmentioning

confidence: 99%

A quantum cascade laser-based Mach–Zehnder interferometer for chemical sensing employing molecular absorption and dispersion

et al. 2018

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We employ a novel spectroscopic setup based on an external cavity quantum cascade laser and a Mach-Zehnder interferometer to simultaneously record spectra of absorption and dispersion of liquid samples in the mid-infrared. We describe the theory underlying the interferometric measurement and discuss its implications for the experiment. The capability of simultaneously recording a refractive index and absorption spectrum is demonstrated for a sample of acetone in cyclohexane. The recording of absorption spectra is experimentally investigated in more detail to illustrate the method's capabilities as compared to direct absorption spectroscopy. We find that absorption signals are recorded with strongly suppressed background, but with smaller absolute sensitivity. A possibility of optimizing the setup's performance by unbalancing the interferometer is presented.

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Section: Introductionmentioning

confidence: 99%

A quantum cascade laser-based Mach–Zehnder interferometer for chemical sensing employing molecular absorption and dispersion

et al. 2018

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“…Additionally, optical isolators in front of the laser are important to suppress any feedback into the laser, which greatly disturbs the stability of the laser's frequency. For the molecular transitions we studied, RAM is mostly removed by background subtraction and optimization of the modulation frequency [9,12]. In general, using the whole tuning range makes the system less sensitive as compared to a situation where the system is be optimized for a specific wavelength.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, various mid-IR coherent light sources have been combined with NICE-OHMS, e.g. difference frequency generation [7], optical parametrical oscillators [8] or quantum cascade lasers [9]. For most of these approaches, the optical field gets modulated via an electro-optical modulator (EOM).…”

Section: Introductionmentioning

confidence: 99%

External cavity diode laser-based detection of trace gases with NICE-OHMS using current modulation

et al. 2015

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Abstract:We combine an external cavity diode laser with noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) using current modulation. With a finesse of 1600, we demonstrate noise equivalent absorption sensitivities of 4.1 x 10 −10 cm −1 Hz -1/2, resulting in sub-ppbv detection limits for Doppler-broadened transitions of CH 4 at 6132.3 cm −1 , C 2 H 2 at 6578.5 cm −1 and HCN at 6541.7 cm −1 . The system is used for hydrogen cyanide detection from sweet almonds. "Design considerations in high-sensitivity off-axis integrated cavity output spectroscopy," Appl. Phys. B 92, 467-474 (2008).

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“…A slight external perturbation (modulation, injection, or optical feedback) is enough to induce sustained pulsating intensities [1]. In the case of infrared chemical sensing, frequency stabilization by injection locking has been successfully used [2]. However, the possibility that a locked state may become unstable and lead to pulsating intensity regimes has never been observed experimentally.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear dynamics of an injected quantum cascade laser

2013

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The stability properties of an injected quantum cascade laser are investigated analytically on the basis of current estimates of the laser parameters. We show that in addition to stable locking, Hopf bifurcations leading to pulsating intensities are possible. We discuss the stability diagrams in terms of the detuning and the injection rate for different values of the linewidth enhancement factor. The analysis indicates domains of coexistence between two stable steady states (bistability) or between a stable steady state and stable periodic oscillations. All predictions are verified numerically by determining bifurcation diagrams from the laser rate equations.

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Stabilization, injection and control of quantum cascade lasers, and their application to chemical sensing in the infrared

Cited by 121 publications

References 32 publications

A quantum cascade laser-based Mach–Zehnder interferometer for chemical sensing employing molecular absorption and dispersion

A quantum cascade laser-based Mach–Zehnder interferometer for chemical sensing employing molecular absorption and dispersion

External cavity diode laser-based detection of trace gases with NICE-OHMS using current modulation

Nonlinear dynamics of an injected quantum cascade laser

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