Abstract: An optical element includes an optical block constructed of a first material having a % transmission of at least 50% throughout a spectral range of 300 nm to 2700 nm through at least a thickness of the optical block. The optical block comprises a surface. A grating layer constructed of a second material is disposed on the surface of the optical block, the grating layer comprising a first surface that is directly in contact with the surface of the optical block and a second surface comprising a plurality of diffraction features forming a diffraction grating.