Assessment of quantum cascade lasers as mid infrared light sources for measurement of aqueous samples

Subsurface Monitor for Dissolved Inorganic Carbon at Geological Sequestration Site Phase 1 SBIR Final Report

“…4 from Reference [7] on the right side). From figure 4, the inferred absorption coefficient is ~6/mm for 1.35g/L, or ~600ppm dissolved CO 2 .…”

“…Comment: Detection limit ~ 120µm [7,12] 4.34µm CO2 Standard deviation 11.3mg/l, detection limit 33.9mg/l 580µm [13] 5.4µm An absorption coefficient of 0.023/µm is measured From the maximum absorption pathlength of 580µm demonstrated at 5.4µm [13], we believe it is reasonable to have a similar path length at 4.34µm (2,340cm -1 ) where the absorption is calibrated to be ~ 0.024/µm. In reference [13] where work was done before 2004 and 580µm of pathlength is demonstrated, they used a weak laser with peak power less than 2mW and duty cycle of 1.5%, or average power only 30µW.…”

Recovery Act: Molecular Simulation of Dissolved Inorganic Carbons for Underground Brine CO2 Sequestration

“…CO 2 dissolved in water gives rise to a strong and characteristic absorption band at 2,342cm -1 [5] meaning that modern infrared spectroscopic techniques might be a useful detection and quantification tool, especially when considering recent innovations such as roomtemperature quantum cascade lasers [6] that allows transmission measurements at extended optical paths. However, when one comes to measuring DIC species using the MIR spectrum there is a great void in the available experimental and theoretical Mid-IR absorption spectra of CO2 (aq), H 2 CO 3 , HCO 3 -and CO 3 2-in water.…”

Microoptoelectromechanical systems-based external cavity quantum cascade lasers for real-time spectroscopy

“…The availability of wavelength-tunable mid-IR lasers has opened up a variety of new applications of mid-IR spectroscopy. [1][2][3][4][5][6] Compared to incoherent light sources such as glow bars or LEDs, tunable lasers have various key advantages, e.g., exceptional spectral power density and resolution, and an almost diffraction limited, collimated output beam. Compact and rugged devices based on semiconductor lasers bear great potential as an enabling technology to transfer mid-IR spectroscopy from laboratory analysis to field use.…”