Shaping Light at the Nanoscale
Focused Electron Beam Induced Deposition (FEBID) and Focused Ion Beam (FIB) processing, have the potential to revolutionize the fabrication of nanoscale optical and photonic devices. These methods enable the creation of structures down to the sub-20 nm regime and true 3D geometries that are unattainable with conventional lithography techniques. The benefits are manifold: mask-free fabrication, site-specific placement, and the ability to create freeform architectures on virtually any substrate. This flexibility makes it possible to design functional nanostructures like:
- Photonic Crystals and Metamaterials: Engineered to manipulate light propagation, guiding, and reflection with unprecedented precision, in particular thanks to the accessibility in 3D space.
- Plasmonic Nanoantennas: Structures that enhance and focus electromagnetic fields at the nanoscale, enabling applications in surface-enhanced spectroscopy (e.g., SERS) and near-field optics (e.g. TERS).
- Chiral Helical Structures: Complex 3D architectures that control circularly polarized light with high efficiency, critical for advanced photonic devices.
For instance, direct-write methods have successfully produced plasmonic antennas with feature sizes below 30 nm, enabling hot spots with field enhancements exceeding 100-fold. Similarly, FEBID allows for the integration of optical components with high purity after gas-assisted purification, improving optical performance for nanoscale resonators and quantum photonics.
The ability to combine deposition, post-growth treatments, and hybrid approaches such as CVD or ALD further enhances the tunability of optical properties, ensuring functional structures with exceptional quality. This capability has opened new frontiers in photonics, from on-chip light routing and plasmon-enhanced sensors to emerging applications in quantum communication and optical metamaterials. By enabling unparalleled control over nanoscale light manipulation, direct-write technologies deliver solutions that not only address existing challenges but also set the stage for the next generation of optical and photonic innovations.
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