29 Apr 2003
Researchers develop the first ceramic-disk laser based on ytterbium-doped yttrium oxide.
A team of scientists from Singapore, Japan and Russia has developed the first ceramic-disk laser based on ytterbium-doped yttrium oxide (Yb:Y2O3). Emitting 0.75 W at 1078 nm, the researchers say that the ceramic crystal was easy to fabricate and is a promising alternative to single-crystal gain materials such as YAG. (Applied Physics Letters 82 2556)
"This is the first demonstration of a ceramic laser based on Yb:Y2O3," Jian Kong from Singapore's Nanyang Technological University told Optics.org. "We have also realised passive Q-switching in the laser and are currently working on passive modelocking. If we succeed, it will prove that ceramic laser materials can fully replace single-crystals, which means great commercial potential."
Polycrystalline ceramics have several advantages compared with their single crystal counterparts. For example, they can withstand a high doping concentration and it is easier to fabricate large samples.
"A single crystal of yttrium oxide has a high melting temperature of 2430°C therefore it is extremely difficult to grow a large-sized single crystal," said Kong. "It's quite easy to fabricate yttrium oxide ceramics because of the low sintering temperature. It's 700°C lower than the melting temperature of the single crystal."
The team's laser is based on a 3-mm-long, 20-mm-diameter, 8% doped Yb:Y2O3 ceramic disk, which was made by Japanese firm Konoshima Chemical. Kong and colleagues pump the crystal with an 11W fiber-coupled laser diode bar emitting at 937 nm. The laser has a maximum continuous wave output of 0.75W at 1078 nm.
Kong says the collaboration is now looking to improve the laser. "We plan to reduce the optical losses of the ceramic samples so as to improve the laser's performance," he said. "We also want to try other Yb-doped materials." The team is now looking for investment from companies that are interested in this field.
It looks as though this field is just about to take off. Ceramic-YAG crystals doped with neodymium have already been developed and will be on display at this year's CLEO and Laser shows.
Jacqueline Hewett is news reporter on Optics.org and Opto & Laser Europe magazine.