Figure 4

From: Mid-infrared surface transmitting and detecting quantum cascade device for gas-sensing

Figure 4

Detector signal over laser current for different concentrations of isobutane (a) in nitrogen and propane (b) in nitrogen. Absorbance (c) of the measured gases with the single mode laser wavelength marked by the dashed line in the inset. Due to higher absorbance of propane at the measurement wavelength the range limit is reached at 70% propane. The minimum detectable light intensity (d) is reached at 90% isobutane and respectively at 70% of propane analyte in nitrogen.