Ultimate limits of FT-IR

Continual improvements in FT-IR have brought us within two orders of magnitude of theoretical limits of the technology, set by the intrinsic noise of the black body spectrum. Further improvements in the technology still require further optimization by step-by-step comparison between actual components performance and their theoretical limit. Among insights from such interferometers, substantial amounts of excess noise in the detectors and nonlinearity in their amplifiers, and an insufficient utilization of the very low aberration levels of interferometers. Beyond this, substantial improvements in spectroscopic sensitivity can be achieved by appropriate choice of the optical interaction. Here the elimination of the 100% line is a particularly desirable goal. The optics of sampling accessories also merit much attention, including throughput matching (and also throughput conservation), optimizing interaction strength, signal strength and detector noise optimization, etc. Finally, data processing can be used to substantially improve the performance capabilities of FT-IR, particularly if we are willing to depart from the conventional data presentations used in IR spectroscopy.