Wafer‐Scale Functional Metasurfaces for Mid‐Infrared Photonics and Biosensing

Abstract

Metasurfaces have emerged as a breakthrough platform for manipulating light at the nanoscale and enabling on‐demand optical functionalities for next‐generation biosensing, imaging, and light‐generating photonic devices. However, translating this technology to practical applications requires low‐cost and high‐throughput fabrication methods. Due to the limited choice of materials with suitable optical properties, it is particularly challenging to produce metasurfaces for the technologically relevant mid‐infrared spectral range. These constraints are overcome by realizing functional metasurfaces on almost completely transparent free‐standing metal‐oxide membranes. A versatile nanofabrication process is developed and implemented for highly efficient dielectric and plasmonic mid‐infrared metasurfaces with wafer‐scale and complementary metal–oxide–semiconductor (CMOS)‐compatible manufacturing techniques. The advantages of this method are revealed by demonstrating highly uniform and functional metasurfaces, including high‐Q structures enabling fine spectral selectivity, large‐area metalenses with diffraction‐limited focusing capabilities, and birefringent metasurfaces providing polarization control at record‐high conversion efficiencies. Aluminum plasmonic devices and their integration into microfluidics for real‐time and label‐free mid‐infrared biosensing of proteins and lipid vesicles are further demonstrated. The versatility of this approach and its compatibility with mass‐production processes bring infrared metasurfaces markedly closer to commercial applications, such as thermal imaging, spectroscopy, and biosensing.

Vacuum ultraviolet nonlinear metalens

“…In light of the design flexibility (45)(46)(47), additional device functionalities can be anticipated, opening the door to new and efficient VUV systems. Considering the recent demonstration of metasurface large-scale fabrication using fully complementary metal oxide semiconductor compatible processes (48,49), we believe this work illustrates a promising strategy toward high throughput manufacturing of compact VUV optical components and devices. Overall, this work lays the foundation for realizing new types of optical components for the VUV region.…”

Trends in Nanophotonics‐Enabled Optofluidic Biosensors

“…[ 195 ] Also, engineering of metamaterials on ultrathin metal oxides and dielectric membranes can be an alternative approach instead of fabricating on hard transparent substrates, because the ultrathin metal oxides and membranes can also provide a wide range of useable transmission windows. [ 196 ]…”

Microporous Multiresonant Plasmonic Meshes by Hierarchical Micro–Nanoimprinting for Bio‐Interfaced SERS Imaging and Nonlinear Nano‐Optics

“…[ 21 ] The optical coupling between the elementary modes of the building blocks can result in multiple hybridized plasmonic modes with spatial overlaps at different wavelengths. [ 15 ] Recently, several multiresonant plasmonic devices have been generated using top‐down fabrication methods such as electron‐beam lithography, [ 22 ] focused ion beam, [ 23 ] deep‐ultraviolet lithography, [ 24 ] laser‐direct‐writing, [ 25 ] and nanoimprint lithography (NIL). [ 17 ] Despite significant research efforts, to date, the existing multiresonant plasmonic devices face challenging issues, such as relatively low hotspot density, weak excitability of multipolar modes, and lack of scalable nanofabrication methods compatible with flexible microporous substrates.…”