Fluid Jet Polishing of Glass Surfaces to Achieve Nanoroughness for Dust Mitigation of Optical Systems.

Optical components and devices, such as camera lenses, thermally controlled optical surfaces, and solar panels, are often exposed to dusty environments, where particulate matter adheres to their surfaces, degrading their optical performance. To address this challenge, we employed a fluid jet polishing (FJP) technique to fabricate nanoroughness on the glass surfaces of exterior elements, mitigating dust adhesion without compromising their high optical qualities. FJP successfully produced various nanoroughness levels by varying the sizes of abrasive particles. The adhesion forces of fine particles at different locations on glass surfaces were quantitatively measured by using atomic force microscopy. The results revealed that the forces were reduced by more than 1 order of magnitude on processed surfaces with increasing local surface roughness, primarily owing to the decreased effective contact area and separation distance, which weakened the van der Waals interactions and electrostatic forces. Furthermore, dust deposition tests using lunar regolith simulant particles with irregular shapes on the processed glass demonstrated the dust mitigation effect, particularly for substrates processed with fine abrasives with a median diameter of 2 μm. The optical properties of the processed glass substrates were also evaluated in terms of haze and transmittance. While some surfaces processed with coarse abrasives exhibited increased haze and reduced transmittance owing to light scattering, substrates processed with fine abrasives maintained high visible transmittance and low haze. The superior optical performance was attributed to the antireflective effects induced by smooth refractive index gradients realized by finely processed glass surfaces, along with effective dust mitigation. FJP offers a flexible and scalable approach for tailoring the surface structure of glass materials, providing practical dust mitigation solutions for advanced optical applications.