Nano-Achiral Complex Composites for Extreme Polarization Optics

Composites made from 2D nanomaterials exhibit exceptional electrical, thermal, and mechanical properties. Their robustness, combined with the ability to control polarization rotation, is crucial for developing hyperspectral optics suitable for extreme conditions. However, the inherent random and achiral shapes of rigid nanoplatelets often disrupt the circular polarization of photons with similar wavelengths.<br/><br/>In this study, we demonstrate that multilayer nanocomposites derived from 2D nanomaterials with intricately textured surfaces can significantly and predictably rotate light polarization, even though they are nano-achiral and partially disordered. The pronounced circular dichroism (CD) observed in these nanocomposite films is attributed to the diagonal patterns of wrinkles, grooves, or ridges, which create an angular offset between the axes of linear birefringence (LB) and linear dichroism (LD). The layer-by-layer (LBL) assembly method allows for precise engineering of polarization-active materials from imprecise nanoplatelets, achieving an optical asymmetry g-factor of 1.0—approximately 500 times greater than typical nanomaterials. These composites also exhibit high thermal resilience, enabling operation at temperatures up to 250 degrees Celsius and facilitating the imaging of hot emitters in the near-infrared (NIR) spectrum. When combined with achiral dyes, LBL-engineered nanocomposites achieve anisotropic factors for circularly polarized emission that approach theoretical limits.<br/><br/>The versatility of this phenomenon is demonstrated through the use of various nanomaterials, such as molybdenum sulfide (MoS2), MXene, and graphene oxide (GO), along with two different manufacturing techniques. This capability paves the way for the computational design and additive engineering of a wide range of LBL optical nanocomponents for ruggedized optics applications.