Ultra-powerful laser makes silicon pump liquid uphill with no added energy

Washington, March 17 : Reports indicate that researchers at the University of Rochester's Institute of Optics have used an ultra-powerful laser to make liquid flow vertically upward along a silicon surface, overcoming the pull of gravity, without pumps or other mechanical devices.

Professor Chunlei Guo and his assistant Anatoliy Vorobyev from the University of Rochester demonstrated that by carving intricate patterns in silicon with extremely short, high-powered laser bursts, they can get liquid to climb to the top of a silicon chip like it was being sucked through a straw.

Unlike a straw, though, there is no outside pressure pushing the liquid up; it rises on its own accord.

By creating nanometer-scale structures in silicon, Guo greatly increases the attraction that water molecules feel toward it.

The attraction, or hydrophile, of the silicon becomes so great, in fact, that it overcomes the strong bond that water molecules feel for other water molecules.

Thus, instead of sticking to each other, the water molecules climb over one another for a chance to be next to the silicon.

The water rushes up the surface at speeds of 3.5 cm per second.

Yet, the laser incisions are so precise and nondestructive that the surface feels smooth and unaltered to the touch.

According to Guo, this work could pave the way for novel cooling systems for computers that operate much more effectively, elegantly, and efficiently than currently available options.

"Heat is definitely the number one problem deterring the design of faster conventional processors," said Michael Scott, a professor of computer science at the University.

So far, designers have not created liquid cooling systems that are cost-effective and energy efficient enough to become widely used in economical personal computers.

Although Guo's discovery has not yet been incorporated into a prototype, he thinks that silicon that can pump its own coolant has the potential to contribute greatly to the design of future cooling systems.