Figure 4.

(A) 100% spectral lines extracted from randomly selected pixels on the sample substrate for the three imaging systems, all normalized to a single scan. (B) Averaged 100% spectral lines shows that the source (shot) noise persisting in QCL systems does not result in the same noise reduction as seen for the FT-IR (random noise) systems. (C) Spatial root-mean-square (RMS) variation in the 100% line shows that the random component of the FPA systems are the same while the LA-based system is significantly less noisy. The noise in an FPA frame from the detector is much smaller (FPA read noise), pointing to the significant potential for improvement in QCL-based systems.