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Implications of orbital angular momentum in quantum physics
2008-11-16 17:35:44
There have been very important developments in optics and quantum mechanics. Despite the importance of these advances, there has been relatively minimal mention of this in the public media.
What scientists have discovered is that by using digital holographic techniques, involving splitting laser beams, they are able to induce orbital angular momentum in the beams, effectively creating light vortices. This orbital angular momentum is seen on a quantum level, causing individual photons to twist. These light vortices have very interesting properties. For example, in the centre of the vortex, there is found the central axis of propagation. At this special point, light revolves at infinite speed, thus causing the light in the centre to vanish. This can be seen as a ring of light when focused by lenses.
With each fork or split of the laser beam adds an additional twist to the photons carried therein. Theoretically, there can be an infinite number of twists in each photon.
There are a number of implications and derivations from this break through. Firstly, from an optics point of view, the application of orbital angular momentum combined with optical tweezers, which are used in the manipulation of microscopic particles, has resulted in the creation of photon-driven motors. Optical tweezers trap particles in three dimensional space and can thereafter be manipulated my the 'steering' of the laser beams. When twisting light is used to manipulate the trapped particles, they begin to rotate. When this particle is a nano-sized gear, and that gear is in turn linked to a chain of such gears, an optical 'pump' can thus be created.
An additional derivation with easily conceivable benefits on a large scale for data transfer is the possible encoding of photons in a base of near infinite value. Traditionally, data has been encoded in binary values, having only one of two possible values (0 or 1). Current quantum encoding techniques enable qubits to be encoded in one of four possible states by suppositioning the polarisation against the spin. Now, however, we could have as many possibilities of values as we like. For example, by encoding photons with a number of twists betwen 0 and 25, we can transmit alphabetical data with a ratio of one character per photon. Imagine the savings in terms of bandwidth such encoding schemes would cause.
This is an exciting time in the field of quantum physics. I look forward to what will come of these recent developments and what practical implementations will develop.
