Wakes of light moving on metallic surfaces made in lab

When a duck paddles across a pond or a supersonic plane flies through the sky, it leaves a wake in its path. Similarly, first-ever wakes of light-like waves moving on a metallic surface that can be controlled and steered have been created.

The researchers from Harvard University have created these wakes, which occur whenever something is travelling through a medium faster than the waves it creates. In the duck's case, these are water waves and in the plane's case, shock waves also known as sonic booms.

"The ability to control light is a powerful one. Nano-optics is the future of nanotechnology and this research furthers our ability to control and harness the power of light on the nanoscale," said Federico Capasso from Harvard's John A. Paulson School of Engineering and Applied Science (SEAS).

Nano-optics has led to holograms, eye-wearable device Google Glass and LEDs. Wakes can exist wherever there are waves, even if those waves are light. In the new experiment, the wakes are called "surface plasmons".

The creation and control of "surface plasmon" wakes could lead to new types of plasmonic couplers and lenses that could create 2D holograms or focus light at the nanoscale.

Being able to control and manipulate light at scales much smaller than the wavelength of the light is very difficult.

"It is important that we not only observed these wakes but found multiple ways to control and steer them," added Daniel Wintz, lead author of the paper.

The discovery was detailed in the journal Nature Nanotechnology.