Integrating Sphere for the Infrared

An integrating sphere of simple construction has been developed for the ir. It has a high efficiency that is not materially affected by aging processes. Experimental measurements of the relative efficiency of this sphere have been made for the wavelength range from 1 micro to 2.6 micro. These data agree with theoretical predictions. It was also predicted that the efficiency of the sphere would increase from 2 micro through to the millimeter wavelength range. The measurements show the ir sphere to have a higher efficiency (2.5 times higher at 2.6 micro) than the conventional MgO-coated integrating sphere.