Photonic cavities are structures that trap light inside them and manipulate its properties. They have many applications in fields such as quantum computing, sensing, and communication. However, creating photonic cavities at the nanoscale is challenging, as they require precise fabrication techniques and high-quality materials.
A recent study published in Nature¹ has overcome this challenge by using a new generation of fabrication technology that combines the scalability of semiconductor technology with the self-assembly of atoms. The researchers used a technique called molecular beam epitaxy (MBE) to grow thin layers of silicon dioxide (SiO2) on a silicon wafer. Then, they used another technique called atomic layer deposition (ALD) to deposit thin layers of gold (Au) on top of the SiO2 layer. Finally, they used a third technique called reactive ion etching (RIE) to remove the unwanted Au layer and create a cavity-shaped pattern on the SiO2 layer.
The result was a photonic cavity that had a diameter of about 10 nanometers and could trap light at its center. The researchers also demonstrated that the photonic cavity could self-assemble into larger structures by using Au nanoparticles as seeds. These nanoparticles acted as templates for the growth of SiO2 layers around them, forming a network of cavities with different sizes and shapes.
The researchers claim that this approach could enable the creation of novel nanoscale devices based on photonic cavities, such as quantum dots, sensors, switches, and modulators. They also suggest that this method could be applied to other materials and geometries, such as graphene, diamond, and carbon nanotubes.
This study is an example of how nanotechnology can revolutionize various fields by creating new possibilities for manipulating light at the nanoscale. Photonic cavities are one of the most promising tools for achieving this goal, as they can offer advantages such as high efficiency, low loss, tunable frequency, and strong interaction with matter.