The mid-infrared (2-10m) spectral region is of enormous scientific and technological interest because it contains the strongest fingerprint absorption bands of a number of pollutant and toxic gases which require monitoring in a variety of different situations (e.g., oil-rigs, coal mines, landfill sites and car exhausts) and in concentrations, ranging from parts per billion to almost 100%. Organic liquids, narcotics and many biological and bio-medical analytes also have fingerprint absorptions in this spectral range. In addition, the atmospheric transmission window between 3 m and 5 m...