What are Diffractive Optical Elements (DOEs) and what are some of the advantages of using them in a lens design?
Diffractive Optical Elements (DOE’s) can focus light just like conventional refractive elements but do so by diffraction (similar to a grating) instead of by refraction. Compared with conventional optical surfaces, which are flat or spherical in shape, DOE’s can be constructed to simulate complex surface shapes to better correct aberrations and improve optical performance. Just like glass optics, DOE’s can be antireflection coated with single or multilayer coatings. DOE’s are useful for conventional broadband imaging applications as well as for many low- and high- power laser applications. Typical DOE sizes range from approximately 4 mm to 250 mm in diameter. For OEM applications, the principal advantages of using DOE’s include: DOE’s usually permit a reduction in the number of optical elements in a design, reducing costs and lens weight. DOE’s often enable optical performance that would be impossible to achieve using conventional optical elements alone.
