We have verified that we could obtain 400W-1kW level of power from a solar-energy-pumped laser. Following this result, we went on to conduct another experiment, using a different type of commercial laser, in order to see if we could in fact obtain magnesium. We illuminated magnesium oxide powder with a 1kW carbon dioxide gas laser for 0.2 seconds. This evaporated the surface layer of the powder to produce gas, and we verified that 30% of the gas was magnesium atoms. What is important here is how efficiently we can obtain pure magnesium. The energy reduction efficiency is defined as the ratio of the amount of energy produced by burning magnesium to the amount of laser energy required to produce the magnesium. The larger this efficiency, the better. The efficiency we obtained from the experiment was 45%, which is very close to our target of 50%.
This process is about the same as the process to recycle magnesium oxide after use. We take magnesium oxide from a used magnesium fuel pack and shine laser light on it to generate magnesium vapor. The resulting magnesium vapor is cooled quickly with inert gas such as argon gas so that magnesium does not have a chance to bond with surrounding oxygen, and then magnesium is deposited on a substrate.