Death of the Dyes...?
With the ever increasing demands of todays software and video, the need for greater storage capacities will only continue. There is still scope for dye based technology as has been shown with the recent explosion in DVD discs, using a smaller wavelength laser to achieve higher data densities. As I researched the subject, I came across a report on some research from Arizona. The article is linked on the links page and is summarised here:
Some materials have been shown to be very sensitive to two electron excitation by laser irradiation. This excitation is sufficient to cause chemical changes on the submicron level in 3 dimensions. These molecules are typically elecron rich and on excitation, they will often transfer an electron to a close neighbour. This leads to a very localised polymerisation reaction where the laser is focussed. 3D polymer patterns could be created using carefully focussed lasers and then read back by scanning in 2 dimensions (from different angles).
The most promising of materials for this new technology is not in fact so far fetched or radical. A discovery was made that when an orange laser is fired into a certain electron donor dye a blue emission is seen. This emission is more energetic that the incident radiation and can only be explained by a 2 electron absorption and subsequent single emission. Research is continuing and we will most likely have to wait quite some time for 3 dimensional polymer disks...