A universal infrared analyzer that includes a tunable optical filter capable of being tuned to one of a selectable set of wavelengths of radiation by a controller accessing a database of a plurality of function specific settings and function specific signatures. The plurality of function specific settings includes settings for al least one of intruder detection, chemical detection, structural integrity detection, medical applications detection, and gas detection. The analyzer also includes a user input interface, for manually selecting one of the function specific settings and one of the function specific signatures. The controller tunes the tunable optical filter to one of the selectable set of wavelengths of radiation based upon the selected one of the function specific settings and a focal plane array generates a signature based upon a target detected by the focal plane array.