We demonstrate an additive manufacturing approach to produce gradient refractive index glass optics. Using direct ink writing with an active inline micromixer, we three-dimensionally print multimaterial green bodies with compositional gradients, consisting primarily of silica nanoparticles and varying concentrations of titania as the index-modifying dopant. The green bodies are then consolidated into glass and polished, resulting in optics with tailored spatial profiles of the refractive index. We show that this approach can be used to achieve a variety of conventional and unconventional optical functions in a flat glass component with no surface curvature.
AbstractGradient index or rugate optical filters are continuous generalizations of the familiar quarterwave stack which find widespread applications in sensor hardening. In the design of a filter or mirror there are infinitely many refractive index profiles n(x) whose wavelength-dependent reflectance R(λ) is specified as a design objective. The relationship between R(λ) and n(x) is nearly that of a Fourier-transform pair. Exploiting this relationship, specifically the physically indeterminate phase of the Fourier transforms, permits constrained optimization of rugate designs. In this contribution we outline the approach of optimal phase modulation and indicate by examples its application to problems in optical limiting.
3D printed gradient index glass optics
