Optical Control of Nanomechanical Brownian Motion Eigenfrequencies in Metamaterials

Abstract

Nanomechanical photonic metamaterials provide a wealth of active switching, nonlinear, and enhanced light-matter interaction functionalities by coupling optically and mechanically resonant subsystems. Thermal (Brownian) motion of the nanostructural components of such metamaterials leads to fluctuations in optical properties, which may manifest as noise, but which also present opportunity to characterize performance and thereby optimize design at the level of individual nanomechanical elements. We show that nanomechanical motion in an all-dielectric metamaterial ensemble of silicon-on-silicon-nitride nanowires can be controlled by light at sub-μW/μm2 intensities. Induced changes in nanowire temperature of just a few Kelvin and nonthermal optical forces generated within the structure change the few-MHz Eigenfrequencies and/or picometric displacement amplitudes of motion, and thereby metamaterial transmission. The tuning mechanism can provide active control of frequency response in photonic metadevices and may serve as a basis for bolometric, mass, and micro/nanostructural stress sensing.

Photonic metamaterial analogue of a continuous time crystal

“…While adiabatically increasing laser power, we initially observe red shifting of the spectral peaks, due to thermal expansion of the nanowires induced by laser illumination, as described in ref. 21. At around 130 μW, the onset of synchronization is observed in a narrowing of the spectrum.…”

Pollen‐Inspired Shell–Core Aerosol Particles Capable of Brownian Motion for Pulmonary Vascularization

“…The irregular never‐ending motion of pollen suspended in water was first observed by Robert Brown with a microscope in 1827, and this motion of suspended particles was later called Brownian motion. [ 33 ] Only particles smaller than 1 µm inhaled into the respiratory tract can penetrate deeply into the bronchi and stay in the alveoli by Brownian motion. A complete trajectory capture and analysis system was established to verify the pollen‐like Brownian motion of the prepared APs (Figure 2B).…”

Metamaterials’ Application in Sustainable Technologies and an Introduction to Their Influence on Energy Harvesting Devices

“…For example, in sensing, they can detect chiral molecules, which are difficult to detect using conventional methods. More recent advancements in chiral metamaterials cover full Stokes polarization perfect absorption, femtomolar bio-detection or optical control of nanomechanical Brownian motion eigenfrequencies [21][22][23].…”