Researchers in Israel have perfected the first ‘Water–wave laser’ which produces a beam through the interaction of light and water waves. The latest discovery will find broad applications in cell biology and new drug therapies. The tiny laser could someday find use as small sensors which combine light waves, sound and water waves. As of now, it will offer an avenue to study the interaction of light and fluid on a scale which is smaller than the width of a human hair. The study was spearheaded by Technion-Israel Institute of Technology and will offer a bridge between two different areas of research which were once considered unrelated to each other i.e. nonlinear optics and water waves.
The laser is an acronym for “Light Amplification by Stimulated Emission of Radiation” and is produced when electrons are excited by energy absorbed from a foreign source. Researchers have shown that water wave oscillation can also emit radiation in the form of laser light.
Researchers, led by Professor Tal Carmon, have been able to produce laser radiation for the first time through water wave radiation within a liquid device. Such a process has never been tried earlier mainly because it was thought that the huge variation in the low frequency of water waves on the surface of a liquid and high frequency of light wave oscillation. This large frequency difference hampers the efficiency of the energy transfer between the light waves and water waves which are essential for the production of lasers.
Scientists found a clever way to solve this problem. They used optical fiber to deliver the light waves to a drop of water and octane mixture. The light waves and the water waves pass through one another over a million times in the droplet. This generates energy which leaves the droplet of water as an emission in the form of laser. It is somewhat like an echo where the sound wave interacts with the surface many times.
To increase the effect in the device researchers have used transparent and highly fluid liquid to augment the light and droplet interaction. A drop of water is a many time softer than the present materials used to produce lasers. This will be advantageous because it will help better control of the lasers.