14 Aug 2003
Scientists in Japan and Russia unveil a ceramic-disk laser based on ytterbium-doped scandium oxide.
A collaboration of scientists in Japan and Russia has built a ceramic-disk laser based on a ytterbium-doped scandium oxide crystal. The Yb3+:Sc2O3 laser is said to emit up to 420 mW at 1094 nm. (Applied Physics Letters 83 1101)
The team says that existing crystal pulling methods do not produce large-scale single crystals with sufficient optical quality to support laser oscillations. But thanks to a method developed by Japan’s Konoshima Chemical Company combining nanocrystalline technology with vacuum sintering, a variety of new polycrystalline ceramic materials have been grown.
The impressive list of ceramic lasers includes systems based on Nd:YAG, Yb:YAG and Nd: Lu2O3 crystals. The latest addition to the list is a laser based on a 13 mm diameter, 2.3 mm thick plate of 2.5 at. % doped Yb3+:Sc2O3.
“Because Yb3+:Sc2O3 has a high melting temperature, it is extremely difficult to grow as a single crystal,” Jianren Lu from Japan’s University of Electro-communications told Optics.org. “But using ceramic sintering, we can fabricate a polycrystalline version of the material. Our technology is the best one to get highly transparent polycrystalline ceramic laser materials and the only one to yield high-quality, large-size Sc2O3 laser materials.”
Lu and colleagues report that the Yb3+:Sc2O3 crystal has an absorption peak between 932 and 955 nm. Because of this broadband absorption feature, the researchers are able to pump the crystal with a 940 nm diode laser, without the need for accurate temperature control of the diode.
For a pump power of 8.8 W, the team recorded a laser output of 420 mW and a corresponding slope efficiency of 9%.
“From the initial work on the material, it has a very good laser performance, low laser threshold, high quantum efficiency and a high thermal conductivity, so of course we have plans to commercialize it,” said Lu. “If commercialized, such laser materials would be sold by Konoshima Chemical Company, Japan.”