Exploring multifunctional, macroscopic structural light absorbers

Stray light can limit the sensitivity and accuracy of optical systems. Traditional solutions, such as coatings, apertures, and microscopic surface structuring, absorb this stray light before it travels further into the system. However, these may be costly, fragile, or difficult to manufacture.

Jan Kaster investigated a new solution: macroscopic structural light absorbers. Inspired by natural porous structures, the author designed three absorbers designed with foam-like minimal surface approximations and sponge-like lattice structures. Simulations showed that the macroscopic structural light absorbers reduced and redirected reflected light intensities by surface shaping the reflections and increasing their number. The author also found that changing the shape of the absorbers can alter the directionality of the reflected light for stray-light control in various optical systems.

Additionally, the geometries of the structures allow for tailored trade-offs in weight, stiffness, and thermal management, enabling multifunctional optomechanical metamaterials.

“This work opens up a multi-domain design space to balance optical with mechanical performance,” Kaster said. “The approach advances beyond traditional methods, like saw-tooth structuring, and offers opportunities to incorporate mechanical metamaterials.”

Through additive techniques, these cost-effective structures can be produced sustainably for research and industrial applications. They are especially well suited for telescopes, imaging spectrometers, and other aerospace optical systems that have strict requirements regarding stray light, weight, and cleanliness, as well as commercial optical systems that require advanced thermal management solutions, such as projectors and luminaires.

Next, the author hopes to advance simultaneous optical and mechanical design methodology to apply these results to optical system design more broadly. This includes fabricating and experimentally validating prototypes of these macroscopic structural light absorbers.

Source: “Macroscopic structural light absorbers,” by Jan M. Kaster, Journal of Applied Physics (2025). The article can be accessed at https://doi.org/10.1063/5.0293446 .

This paper is part of the Mechanical Metamaterials Collection, learn more here .