World’s first water-wave laser

•  Researchers have developed the world’s first water-wave laser, demonstrating that lasers can be created by interactions between light and water waves.

About water-wave laser:

• A typical laser can be created when the electrons in atoms become 'excited' by energy absorbed from an outside source, causing them to emit radiation in the form of laser light.
• Main reason water-wave lasers haven’t been explored in the past is because the frequency of water wave oscillation on the surface is a whole lot lower than a light wave, suggesting that the production of a laser emission would probably be highly inefficient.
• To overcome that slow oscillation, they created a device that used an optical fibre to deliver light to a small droplet of octane and water.
• This tiny bit of light introduced to the droplet interacts with the waves of the water, bouncing back and forth until enough energy has built up that the light can leave the droplet.
• The interaction between the fibre optic light and the minuscule vibrations on the surface of the droplet are like an echo, "where the interaction of sound waves and the surface they pass through can make a single scream audible several times.
• In order to increase this echo effect in their device, the researchers used highly transparent, runny liquids, to encourage light and droplet interactions."
• The main part is that the introduced light from the optical fibre is enough to deform the water droplet.
• While it seems obvious that any sort of energetic particle smashing into a super tiny droplet of water would make it deform a bit, normal optomechanical devices are hardier.
• This deformation, about a million times greater than that of current laser-producing devices, allows for greater control, which could be extremely helpful once the technology is developed further and used in a laboratory setting to study cells.

Analysis:

• This is the first bridge between two areas of research that were previously considered unrelated to one another: nonlinear optics and water waves.
• For now, the water-wave laser offers a “playground” for scientists studying the interaction of light and fluid at a scale smaller than the width of a human hair.
• In future, the laser could be used in tiny sensors that combine light waves, sound and water waves.
• The laser may also be used in ‘lab-on-a-chip’ devices to study cell biology and test new drug therapies.

By: Vishal