RESUMO
Increasing the interaction between light and mechanical resonators is an ongoing endeavor in the field of cavity optomechanics. Optical microcavities allow for boosting the interaction strength through their strong spatial confinement of the optical field. In this work, we follow this approach by realizing a sub-wavelength-long, free-space optomechanical microcavity on-chip fabricated from an (Al,Ga)As heterostructure. A suspended GaAs photonic crystal mirror is acting as a highly reflective mechanical resonator, which together with a distributed Bragg (DBR) reflector forms an optomechanical microcavity. We demonstrate precise control over the microcavity resonance by change of the photonic crystal parameters. We find that the microcavity mode can strongly couple to the transmissive modes of the DBR. The interplay between the microcavity mode and a guided resonance of the photonic crystal modifies the cavity response and results in a stronger dynamical backaction on the mechanical resonator compared to conventional optomechanical dynamics.
RESUMO
The emissivity of an opal photonic crystal loaded with thermochromic VO2 nanoparticles is studied through optical calculations, highlighting the influence of the structure by comparison with a homogenized model. Parameters are first set to maximize the structure influence on material emissivity. Then, a full study of the influence of the VO2 concentration is made to identify, on one hand, cases with the highest structure impact, and on the other hand, interesting cases for applications such as energy-efficient coatings for buildings, satellites, and camouflage applications.
