Silicon Mie Voids Achieve Independent Nanoscale Emission Tuning and Loss Minimisation

Scientists are tackling the challenge of precisely controlling light emission at the nanoscale, a crucial step towards advancements in devices ranging from brighter LEDs to more sensitive nanosensors. Yuchao Fu, Ilia Lykov, and Sergejs Boroviks, from the Nanophotonics and Metrology Laboratory at EPFL, alongside Nai-Quan Zhu et al from Shanghai Jiao Tong University, demonstrate a novel approach using silicon Mie voids , tiny air cavities , to independently tune both the strength and efficiency of light emission. This research is significant because it overcomes previous limitations in simultaneously enhancing excitation and modulating emission yield, offering a pathway to create programmable, high-density multimodal displays, as evidenced by the successful encoding of the EPFL and SJTU logos within nanophotonic patterns.

Silicon Mie Voids Control Light Emission

This research introduces a novel platform for manipulating Spontaneous emission, a fundamental process crucial for light-emitting devices, optical encryption, super-resolution imaging, and nanosensors. The team achieved precise control over emission characteristics by inverting the geometry of conventional solid-particle structures, creating air-defined cavities that minimise optical losses and maximise tunability. Experiments show that the unique configuration of Mie voids accelerates Radiative decay, confirming the potential for advanced nanophotonic device development. The study unveils a new method for tailoring light-matter interactions, moving beyond traditional plasmonic systems and all-dielectric Mie resonators.
Unlike previous approaches that often struggle with fabrication complexity or limited spatial control, Mie voids offer a comparatively facile fabrication process alongside flexible spatial arrangement and lifetime shortening with reduced non-radiative decay. This work establishes that vacuum, in the form of Mie voids, can strongly modify the local optical density of states and control molecular quantum emission, a previously unexpected effect. The research proves that by localising resonant electromagnetic fields predominantly in air, Mie voids facilitate stronger coupling between quantum emitters and both cavity modes and radiation channels, effectively reducing the effective mode volume and enhancing the optical LDOS. This breakthrough establishes Mie voids as a promising platform for chip-scale, room-temperature emitters with engineered radiative lifetimes, directional luminescence, and on-demand spectral shaping, extending spontaneous emission control to practical applications in nanolasers and super-resolution imaging. The team’s innovative approach overcomes the limitations of solid-particle Mie resonators, which typically confine mode volume within the high-index dielectric material, leading to weak coupling with emitters in the surrounding low-index environment.

Silicon Mie Voids for Emission Tuning and Decay

Researchers decomposed spontaneous emission into three channels: intrinsic nonradiative decay, radiative emission to the far field, and absorption in the surrounding dielectric medium, meticulously characterising resonant coupling and emission dynamics using dimensionless factors. The. Calculations, performed for a dipole emitter 150nm from the centre of a 100nm-diameter silicon Mie particle, confirmed the energy-conservation relation FFpp= μ + μ1, validating simulation reliability and simplifying subsequent analyses by eliminating the need for full-volume absorption integration. This innovative approach reduced the computational burden to surface-integrated radiated power evaluation for determining the far-field radiation factor.
Further analysis revealed a strong dependence of quantum emission enhancement on emitter orientation, highlighting the anisotropic nature of the emitter-resonator coupling. The study demonstrated that substantial emission enhancement requires low dielectric absorption, specifically μμ ൫FFpp−1൯(1 −qq0). To accurately model practical experimental setups, the far-field receiver surface was defined as an infinite horizontal plane above the void, conceptually projecting a spherical receiver onto a planar surface.,.

Silicon Mie voids enhance light emission control

Experiments revealed that these voids, unlike traditional solid-particle geometries, invert the resonant field maxima into low-index air, significantly reducing optical losses and enabling tighter field confinement. The team measured a substantial acceleration of radiative decay, confirming the effectiveness of the void configuration in enhancing emission characteristics. Measurements confirm that this approach allows for precise control over the photonic environment surrounding emitters, a crucial step towards advanced nanophotonic devices. Scientists recorded the creation of complex patterns at the nanoscale, showcasing the potential for advanced imaging and information storage applications.

This innovative design localizes resonant electromagnetic fields predominantly in air, facilitating enhanced interaction with external emitters and reducing effective mode volume. Tests prove that Mie voids offer a significant advantage over plasmonic nanostructures, which suffer from high absorption losses, and photonic crystal slabs, which require sophisticated fabrication techniques. The breakthrough delivers a facile fabrication process, thanks to the larger feature sizes of Mie voids, alongside directional emission, flexible spatial arrangement, and lifetime shortening with reduced non-radiative decay. Measurements indicate that this platform paves the way for chip-scale, room-temperature emitters with engineered radiative lifetimes, directional luminescence, and on-demand spectral shaping, extending spontaneous emission control to practical applications in nanolasers and super-resolution imaging.

Mie voids enhance emission, minimise loss,

The key finding is that Mie voids minimise optical losses while simultaneously enhancing radiative decay, achieved by concentrating both excitation fields and resonant emission modes within the air void itself, facilitating improved coupling with internal emitters. This differs from conventional silicon particles where fields are largely confined to the solid dielectric, limiting access for external emitters. The authors acknowledge that the modelling initially employed a simplified cylindrical cavity shape, and future work could explore the impact of more realistic truncated conical profiles commonly found in fabrication. Further research will likely focus on expanding the application of Mie voids to create programmable, high-density multimodal displays and advanced nanophotonic devices, building upon this foundational work.