Scientists from the Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) of the Chinese Academy of Sciences (CAS), along with their collaborators, have recently discovered micromanipulation with tunable opto-fluidic curvature. The study was published in Laser Photonics & Reviews.

In a groundbreaking development, researchers have unveiled a novel method for manipulating micro and nanoparticles at liquid interfaces, using radiation pressure-induced deformed surfaces. This active, non-invasive, and contactless technique, while promising, faced a challenge due to the relatively small magnitude of radiation force in normal incidence. However, a solution has emerged by exploiting the unique properties of total internal reflection (TIR) in retro-reflection mode.

The key innovation involves creating a high-amplitude bulge on the water surface, leveraging TIR to migrate particles as effectively as the traditional micro-post paradigm. This method addresses the challenge by utilizing interferometric techniques to measure the bulge height and demonstrating the underlying physics through an imitated particle with a capillary charge.

Moreover, the researchers have demonstrated the versatility of this technique by shaping the liquid interface with increasing complexity using two pump lasers. By tuning the relative pump laser intensity, particles can be precisely migrated in the desired direction, offering a powerful tool for controlled particle movement at interfaces. This breakthrough provides a non-invasive and contactless means to remotely actuate almost all types of micro/nanoparticles at the liquid surface, unlocking a myriad of applications in both physical and biological domains.

As the scientific community looks towards the future, this method not only overcomes existing challenges in microparticle manipulation but also introduces a transformative approach that holds promise for various technological and medical applications. The marriage of optics and fluid dynamics in this innovative technique opens up new possibilities for researchers and engineers seeking advanced methods for precise particle control.