Mid-Infrared Reflectance Spectroscopy Based on External Cavity Quantum Cascade Lasers for Mineral Characterization.

Mineral characterization using tunable external cavity quantum cascade lasers for mid-infrared reflectance spectroscopy is presented. Reflection spectra taken on common minerals are shown along with their spectral variations. Measurements at different incident angles were also obtained to mimic in the field applications. Finally, spectra were obtained on mineral mixtures and their analysis assesses the quality and usability of the technique for mineral characterization.

Mid-Infrared Reflectance Spectroscopy of Oil Sands Minerals Based on Tunable Quantum Cascade Lasers.

Minerals play an important role in the oil sands extraction efficiency. It is thus important to assess the major mineral abundance in oil sands ores. This paper presents the application of tunable quantum cascade lasers for mid-infrared reflectance spectroscopy on oil sands minerals. The investigations and results show a new tool to determine oil sands mineral type and to determine potentially quartz and clay contents.

Low-threshold lasing at 1975 nm in thulium-doped tellurite glass microspheres.

Thulium-doped (Tm-doped) tellurite glass microspheres are used as laser media. Emission lines at wavelengths near 1975 nm are observed. The onset of laser emission is achieved with 8.6 and 30 µW of coupled pump power and injected pump power, respectively, at a wavelength of 1554 nm. To the authors' knowledge, these are the lowest laser threshold values recorded for a Tm-doped tellurite glass microcavity. Intrinsic Q-factors above 10(6) for the undoped tellurite glass microspheres assert the quality of the fabrication processes. An optical intrinsic Q-factor comparison between Tm-doped tellurite and undoped tellurite microspheres shows that ion absorption is the dominant loss source at pump wavelengths. Lower lasing threshold powers and higher power conversion are observed at longer pump wavelengths in agreement with theoretical models.

Cascaded Raman lasing in packaged high quality As2S3 microspheres.

We report the observation of cascaded Raman lasing in high-Q As2S3microspheres. Cascaded stimulated Raman scattering emission is obtained up to the 5th order for a pump wavelength of 1557 nm and up to the 3rd order for a pump wavelength of 1880 nm. High-Q As2S3microspheres are used in a self-frequency locking laser setup without an external laser source. Threshold curves measurements are presented and follow the expected coupled mode theory behavior with a sub-mW threshold pump power.

Raman lasing in As2S3 high-Q whispering gallery mode resonators.

We report the first observation of a nonlinear process in a chalcogenide microresonator. Raman scattering and stimulated Raman scattering leading to laser oscillation is observed in microspheres made of As2S3. The coupled pump power threshold is as low as 13 µW using a pump wavelength of 1550 nm. The quality factor of the chalcogenide microresonator is also the highest ever reported with Q>7×10(7).

Intrinsic quality factor determination in whispering gallery mode microcavities using a single Stokes parameters measurement.

Determination of the intrinsic quality factor of a loaded whispering gallery mode microcavity can be important for many applications where the coupling conditions cannot be tuned. We propose a single-scan technique based on a Stokes parameters analysis to extract the intrinsic quality factor and therefore determine the coupling regime. We propose a simple model for this analysis and present experimental measurements, which are in very good agreement with the model.