Fig. 2 | Scientific Reports

Fig. 2

From: Mid-IR standoff measurement of ageing-related spectroscopic changes in bitumen in the 6 µm (1700 cm−1) region. Part 2: Instrument development and results

Fig. 2

Tuning characteristics of (a) the reference ICL and (b–d) the 3 measurement QCLs at different laser temperature setpoints. The shaded bars on the QCL graphs indicate the locations of the water absorption windows. The tuning curves illustrate the degree to which the width of the water windows limited the accessible level of current modulation.

Back to article page