Liquid photonic microcavity yields deformable soft microresonator that can be gradually tuned

Deformable photonic microcavities made from liquids offer a wide range of characteristics that increase control over light. Most approaches to such microcavities, however, employ discrete sets of resonators.

Douvidzon et al. announced an experimental soft microresonator that is reversible and continously deformable and can control resonance split and directional emission, showing the promise of optical tweezers for continuous tuning of microcavities. Using computerized holographic tweezers that function as an optical deformer, the group was able to gradually deform the shape and change the functionality of a droplet whispering gallery cavity.

The work marks an early effort to bring the optical tweezers, a tool that has found use in applications from engineering microfluidics to isolating single biomolecules, in the field of photonics.

“Until now, optical components, such as resonators, were fabricated to maintain their shape and optical spectrum,” said author Mark Douvidzon. “Our method permits continuously changing the resonant wavelength of the cavity and its shape, while it is operating.”

Liquid microcavities provide an array of features over their solid counterparts, including a mechanically softer cavity and the interaction between light and capillary waves.

The group continuously deformed spherical cavities to rectangular ones, switched to a directionally emitting mode-of-operation and split a resonant mode to a 10-GHz separated doublet. They showed their liquid microcavity was capable of optional solidification, bolstering the approach’s use in printing optical-circuits and multiwavelength optical-networks.

Douvidzon hopes the paper stokes further interest in photonics innovation, particularly in seeing methods scale up with today’s trend of improving spatial light modulators and tweezers. He looks to someday realize a 3D photonic circuit.

Source: “Toward transformable photonics: Reversible deforming soft cavities, controlling their resonance split and directional emission,” by Mark Leonidovic Douvidzon, Shai Maayani, Harel Nagar, Tamir Admon, Vladimir Shuvayev, Lan Yang, Lev Deych, Yael Roichman, and Tal Carmon, APL Photonics (2021). The article can be accessed at https://doi.org/10.1063/5.0053154 .