Hiyori Uehara

Efficient continuous wave and quasi-continuous wave operation of a 28 μm Er:Lu_2O_3 ceramic laser

We have demonstrated a highly efficient 2.8 μm Er-doped Lu2O3 ceramic laser and investigated the lasing dynamics by time-resolved spectroscopy. During room-temperature continuous wave operation, a slope efficiency of 22% was achieved with a high-quality transparent ceramic. To our knowledge, this is the highest slope efficiency obtained by an Er:Lu2O3 ceramic laser. In addition, an output peak power of 1.2 W was obtained during quasi-continuous wave operation. Time-resolved spectroscopy showed that the emission wavelengths exhibited a red shift from 2715 to 2845 nm, which indicated that continuous wave operation may be possible at 2740 and 2845 nm.

Characterization of Er:Lu 2 O 3 ceramic lasers for efficient emission at 2.8 μm

High-power mid-IR lasers at 3 μm wavelength have many potential applications in medical and industrial fields because of the strong absorption by water at that wavelength region. Recently, erbium-doped cubic rare-earth sesquioxide crystals (e.g. Lu<inf>2</inf>O<inf>3</inf>, Y<inf>2</inf>O<inf>3</inf>, and Sc<inf>2</inf>O<inf>3</inf>) are gaining attention as laser sources due to their lower phonon energies and higher thermal conductivities compared with YAG. In particular, Er:Lu<inf>2</inf>O<inf>3</inf> is known as suitable source because the thermal conductivity stays high even at a high doping level [1]. The high quality polycrystalline transparent ceramics of Lu<inf>2</inf>O<inf>3</inf> which became available in recent years will open up the possibility of high-power mid-IR lasers because of the advantages such as mechanical strength and manufacturability of large volume.