Shanxi University makes headway in optical traction research

Chen Jun, professor of the Institute of Theoretical Physics at Shanxi University, along with Li Xiao and Jack Ng from Hong Kong Baptist University and Lin Zhifang from Fudan University, recently published a research article on optical traction in Science Advances.

Optical tractor beams, first proposed in 2011 and experimentally demonstrated later, offer the ability to pull particles against light propagation. However, their limited microscopic range severely restricts applicability.

The dilemma is that a long-range Bessel beam, the most accessible beam for optical traction, has a small half-cone angle, θ0, which makes pulling difficult, according to the article.

Chen and his associates overcame the dilemma and achieved long-range optical pulling at θ0 ≈ 1° using several methods, including transverse isotropy, Snell’s law, antireflection coatings (or impedance-matched metamaterials), and light interference.

Due to their work, macroscopic optical pulling can now be achieved in both a medium and a vacuum, with high tolerance for the half-cone angle and for the frequency of light.

The article discusses research progress on optical tractor beams, which is of great value to the development of optical pulling.

Related: https://advances.sciencemag.org/content/5/3/eaau7814