An infrared filter for an optical metrology tool includes a substrate having film stacks on opposing surfaces thereof. A first film stack can be used to reflect ultra-violet radiation and transmit radiation at non-ultraviolet wavelengths. The second film stack can be used to reflect visible to near-infrared radiation and transmit infrared radiation. The combination of film stacks can therefore extract infrared radiation from a broadband beam, with the remaining ultra-violet radiation and visible to near-infrared radiation forming the product of the filter. The filter can be used as part of the illumination or collection side optics in a broadband optical metrology tool.