High-Transparency 3D Micro-Optics of Hybrid-Polymer SZ2080™ Made via Ultrafast Laser Nanolithography and Atomic Layer Deposition

Abstract

Laser Direct Writing (LDW) allows for the fabrication of complex free-form structures, particularly advantageous in micro-optic applications when used in conjunction with high-performance polymers, such as SZ2080™. Nonetheless, high-complexity and integrated micro-optical elements often manifest multiple interfaces, resulting in increased Fresnel reflection losses. While conventional physical vapour deposition processes are usually employed in the manufacture of high-precision optics, such methods are incapable of producing uniform coatings on micrometer scale complex free-form structures. Atomic Layer Deposition (ALD) is an alternative highly flexible coating process, able to coat intricate geometries down to nano-scale. We propose the use of LDW in conjunction with ALD in the production of highly efficient anti-reflective (AR) coated functional free-form sub-100 μm micro-optic elements - multi-layer platforms and triplet objectives. Low-temperature deposition of aluminum oxide and titanium oxide AR coating proved to be compatible with SZ2080™ polymer structures, as no loss of optical function was observed. In addition, a substantial increase in transmittance, up to 99.9% per interface, is seen. Such findings prove suitable for use in highly efficient compound micro-lens arrays, greatly integrated solutions, and low-loss photonic components making them readily available for Photonic Integrated Circuits (PICs).