Demonstration of vacuum levitation and motion control on an optical-electrostatic chip

Levitation of microscopic objects in a vacuum and control of their movement while suspended was first demonstrated several decades ago. Since then, various research groups have been working on new approaches to control levitated objects in vacuum with greater degrees of freedom.

While most experiments performed to date have relied on optical techniques, some teams have recently begun using hybrid experimental platforms that combine concepts rooted in atomic physics. These hybrid platforms allow more control over the movement of levitating objects and unlock new possibilities such as force and torque sensing or precise acceleration.

Researchers at ETH Zurich recently demonstrated the levitation of a silicon dioxide nanoparticle in a high vacuum on a hybrid photonic-electric chip. Their proposed experimental platform, outlined in a paper published in Nature NanotechnologyIt was found to enable robust levitation, precise position detection, and dynamic control of the nanoparticle in vacuum.

“With the isolation from the environment and the precise control of mesoscopic objects, vacuum levitation has evolved into a versatile technique that has already benefited various scientific fields, from force sensing and thermodynamics to materials science and chemistry,” wrote Bruno Melo, Marc T. Cuairan and colleagues to your newspaper.

“It also holds great promise for advancing the study of quantum mechanics in the unexplored macroscopic regime.”

Despite recent advances in vacuum levitation and control of particle motion, most previously established experimental methods rely on complex strategies and/or bulky equipment. This severely limits their real-world applications, making them impractical for developing new technologies.

Some researchers have thus attempted to miniaturize vacuum levitation platforms using electrostatic and optical traps. However, the levitation achieved using most of their proposed approaches was not robust enough to be applied to closed devices such as cryostats and portable devices.

Melo, Cuairan and co-workers presented a new hybrid photonic-electric platform that enables robust levitation, position detection and dynamic control of nanoparticles on a chip. Unlike other platforms, their proposed method does not require bulky lenses and optical equipment.

“We demonstrate high-vacuum levitation and motion control of a silica nanoparticle on the surface of a hybrid optical-electrostatic chip,” wrote Melo, Cuairan and their colleagues. “Combining fiber-based optical trapping and sensitive position detection with cold damping using planar electrodes, we cool the particle motion down to a few hundred phonons.”

In initial tests, the team’s proposed on-chip vacuum levitation and motion control platform achieved remarkable results with signal-to-noise ratio and optical displacement detection capabilities comparable to those of other approaches that rely on bulky optical devices. By combining their platform with planar electrodes for active feedback cooling, the researchers were also able to cool the silica nanoparticles and reduce their motion in 3D.

A new approach to on-chip vacuum levitation and motion control pioneered by this team at ETH Zurich could soon open new opportunities for quantum research and technology development. In their next studies, Melo, Cuairan and their colleagues plan to continue to refine their platform, for example by using refractive microlenses to further increase its detection sensitivity and by integrating more sophisticated optical elements (such as fibrous cavities).

“We envision our fully integrated platform as the starting point for on-chip devices combining integrated photonics and nanophotonics with precisely designed electrical potentials, increasing control over particle motion toward complex state preparation and readout,” Melo, Cuairan and their colleagues wrote.

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