Bending Light for Better Imaging

A team of researchers at the Georgia Institute of Technology and Harbin Institute of Technology in China have developed a novel imaging system using light beams that can bend, curving around objects and getting brighter as they travel, enhancing image quality and imaging depth.

They call it “Airy-beam Tomographic Microscopy” – which is the name of the technology, and the title of a paper published recently in the journal Optica.

“Normally, optical beams move along a straight line in free space, but there’s a special type of optical beam, an Airy beam, which is self-accelerating and non-refracting which can move along a bending trajectory,” explains Shu Jia, assistant professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory, and the paper’s corresponding author.

Jia’s lab aims to make an impact on biological and translational research through innovative imaging science. Toward that end, the researchers have advanced their expertise in a wide range of imaging instrumentation and techniques, such as super-resolution, adaptive optics, light-field, miniaturized, light-sheet, computational microscopy and endoscopy.

With Airy beam tomographic microscopy (ATM), they have introduced high-resolution, volumetric, inertia-free imaging for biological specimens. Exploiting the highly-adjustable Airy trajectories in the 3D space, the system transforms the conventional telecentric wide-field imaging scheme (which requires sample or focal-plane scanning to acquire 3D information). And the results are dramatic.

“We demonstrate that this system can achieve near-diffraction-limited resolution – so there is no compromise in resolution in all three dimensions, with 10 times improvement in depth of focus,” says Jia, who also is a researcher in the Petit Institute for Bioengineering and Bioscience at Georgia Tech.

It’s because the Airy-beam is non-spreading, or non-diffracting, “which means you can capture information from a much deeper range in the biological sample,” according to Jia. “Also, this system can be very stable, so it would work well for live imaging.”

The work builds on the development of self-accelerating Airy beams over the past decade or so, which has led, in recent years, to the emergence of Airy-beam-enabled optical imaging. But these methods haven’t fully explored the highly adjustable Airy trajectories in the entire 3D space for volumetric imaging. The Jia lab’s work changes that, utilizing the self-accelerating propagation trajectory of an Airy beam to form a perspective view of the object.

Therefore, given sufficient perspective views by manipulating the Airy trajectories, the entire volume can be computationally synthesized in a tomographic manner – a scheme that exploits the self-acceleration and maneuverability of Airy beams.

“Interestingly, here we’re just talking about an optical method, but this scheme can be generalized to other wave physics,” Jia says. “It can be translated to non-optical waveforms, such as acoustic, plasmonic, and electronic waves. We anticipate this system will achieve applications in a wide range of biological systems, spanning molecular, cellular, and tissue levels, offering a promising paradigm for 3D optical microscopy.”

In addition to Jia, the authors included lead author Jian Wang (researcher at the Harbin Institute of Technology, China; former postdoc in Jia lab), Changliang Guo (research fellow at UCLA; former postdoc in Jia lab), Xuanhen Hua and Wenhao Liu (graduate student researchers in Jia lab).