Scientists discover new property of light based on Angular Momentum

Scientists from Trinity College Dublin’s School of Physics and CRANN Institute have discovered a new property of light based on Angular Momentum.
The scientific breakthrough discovery has potential to alter the basic understanding of fundamental nature of light.
Key facts

• The discovery was made by passing light through crystals. During it passage, unexpected new property of light, based on the concept called ‘angular momentum’ was observed.
• Earlier, physicists always thought that in all forms of light the angular momentum (measures how much a beam of light is rotating) will be a multiple of Planck’s constant (physical constant that sets the scale of quantum effects).
• But in the new discovery scientists discovered very different behavioural of angular momentum.
• They found angular momentum of each photon (a particle of visible light) takes only half of this value i.e. each photon have half-integer values of angular momentum.
• This new property causes a beam of light to be confined to fewer than three dimensions.
• Significance of Discovery: Help in study of light waves in areas such as secure optical communication which will open up new means for faster internet connections.
• Enable to study new possibilities including particles whose quantum numbers are fractions of those expected.
• For the first time the discovery shows how quantum mechanics works for particles that are free to move in only two of the three dimensions of space and can be realised with light.

Month: Current Affairs - May, 2016