A New Solar Laser Use Magnesium as a Source of Energy.

A new kind of efficient, solar-powered laser has been developed by researchers at the Tokyo Institute of Technology, in Japan. They hope to use the laser to help them realize their goal of developing a magnesium combustion engine.
According to the professor of mechanical engineering and science, Takashi Yabe, their goal is to create a powerful laser that can effectively combust magnesium from sea water.

Magnesium has great potential as an energy source because it has an energy storage density about 10 times higher than that of hydrogen, says Yabe. It is also highly abundant, with about 1.3 grams found in every liter of seawater, or about 1,800 trillion metric tons in our oceans, he says.

Yabe also informed that magnesium oxide produced from the reaction can again be converted into magnesium. This recycling process demands great temperature. In order to operate magnesium combustion engine, solar power is required for the lasers. Lasers concentrate sunlight on neodymium-doped yttrium aluminum garnet. Usually, solar powered lasers depends a lot on large mirrors. However, Yabe along with his colleagues have developed an immensely powerful laser.

The other innovation of Yabe's laser is the use of a small Fresnel lens instead of large mirror lenses. Fresnel lenses reduce the size and amount of material needed to build a lens by breaking it into concentric rings of lenses. Typically, 10 percent of incident light is focused on the crystal, whereas with the Fresnel, it's around 80 percent.

This was made possible with the addition of chromium. Yabe stated, “Thus the efficiency from sunlight to laser is greatly enhanced.” Instead of large mirrors, they have sued small Fresnel lens. Yabe also informed that, “In our case, we used only 1.3 meter squared and achieved 25 watts,” he further added, “So we are expecting 300 to 400 watts with the four-meter-squared Fresnel lens.”