An optical element includes a refractive material, a plurality of relay curvatures, and dichroic relay mirrors configured as an optical relay. The plurality of relay curvatures is formed in the refractive material. The dichroic relay mirrors include a dichroic reflective layer disposed on the plurality of relay curvatures and immersed in the refractive material. The dichroic reflective layer reflects a first spectrum light and passes light outside the first spectrum light. The first spectrum light may be infrared light.