Our IRDK telescopes include a Dall-Kirkham optical design with coatings that are optimized to transmit in infrared or ultra violet wavelengths. There are no refractive lens, only reflective components to the design. For IR application, reflective coatings are a protected gold which give better than 98% reflectivity from .65 micron (650nm) to 5 micron (5000nm). This design is ideal for infrared astronomy or LIDAR applications. UV optimized coatings can provided as well.