An infrared (IR) source apparatus that includes a desired infrared source element coupled to an insulating housing so to minimize overall source inefficiency at desired optical bandwidths is introduced. The insulation itself is machined or configured in a way so that the infrared source element is in contact with a designed cavity in the insulation so that the IR source image becomes the average of the insulation material and the infrared element. Such an arrangement of the present invention increases the emissivity of the IR source below about 1500 wave numbers, more often, below about 1100 wave numbers, and even more particularly, at about 1079 wave numbers. Accordingly, the combined emissivity of the infrared source and the insulation substantially enhances spectral emission and eliminates or reduces spectral artifacts from the formation of oxides on the infrared source surfaces.
