AIR Scientists Propose New Method on Laser Beam Propagation through Air Turbulence

A study on the "Pin-Like Optical Beams to Penetrate Turbulence" published by the scientists from the Aerospace Information Research Institute (AIR) under the Chinese Academy of Sciences (CAS) was on the list of “30 exciting peer-reviewed optics researches” that had emerged around the world in 2019, according to a news on the annual highlights special issue recently released by the Optical Society of America (OSA), which has been highlighting a list of top 30 exciting optical research of the year on its annual special issue since 1990.

Ever since the innovation of laser, humans have long dreamt of shape-preserving light beams that could propagate robustly without broadening and distortion - even through turbulent media. Ideally, one might achieve that goal using adaptive optics, diffraction-free beams such as Airy beams, or optical solitons. But complicated or unrealistic design requirements often make such techniques impractical for free-space applications.

AIR scientists have found that the effect of air turbulence on laser beam is caused by introducing random transverse wavevectors. Based on this idea, they have proposed a method to construct a special laser field that can eliminate transverse wave vectors during propagation to reduce the effect of air turbulence.

To demonstrate the validity of this method, the research team generated a pin-like optical beam and adopted it to propagate through air turbulence over a kilometer distance for the first time. Compared with the longest propagation distance of Bessel or Airy beams in the world (meters level), this method has improved the propagation distance up to three orders longer. Meantime, the production efficiency reached more than 90%, as shown in Figure 1.

The method and technology are expected to offer a new approach to reduce the air turbulence effect to laser beam, and thereby improving the working performance of some laser systems such as laser communication and laser detection, especially when air turbulence is unavoidable.

This research was first published at the Conference on Lasers and Electro-Optics (CLEO) on May 5, 2019, and was fully published in the journal of Applied Physics Letters-Photonics.