Light travelling at less than the speed of light.

It's a challenge for the classical physics and our knowledge of science. In all of our text books we have read that light velocity depends on the medium in which it travels and is maximum in air or vacuum that is approximately 3*10^8 meter per second. 

But a new research paper published from University of Glasgow and Heriot-Watt University describe how they have managed to slow photons(light carrier) in free space for the first time, and they are able to do this by applying a mask to the optical beam which provided the photons for the experiment. The mask forced the photon to change its shape and travel slower than the speed of light.

In the experiment the scientists took two beams of light emitting photons to race together one was normal and the other beam was masked which changed the shape of the photons passing through it, this was one of the proof that light is of dual nature that is wave and particle, as only shape of waves can be changed. And when the photon after passing through mask was again in free air it took a very very small time to complete the 1 meter long race with the normal photon. This shows that once pattern has been imposed - even now the light is no longer in the mask, it's just propagating in free space - the speed is still slow. 

Professor Padgett the Scientists associated with the experiment added: “It might seem surprising that light can be made to travel more slowly like this, but the effect has a solid theoretical foundation and we’re confident that our observations are correct.

“The results give us a new way to think about the properties of light and we’re keen to continue exploring the potential of this discovery in future applications. We expect that the effect will be applicable to any wave theory, so a similar slowing could well be created in sound waves, for example".