Transparent Gahnite Ceramics Cr3+:ZnAl2O4 – Novel Red-Emitting Material

Trivalent chromium ions (Cr 3+ ) located in octahedral (O h ) sites in crystals such as Alexandrite (BeAl 2 O 4 ) are attractive because of large emission bandwidth enabling the development of broadly tunable and mode-locked [1] lasers. It is interesting to search for other promising laser host materials for Cr 3+ doping. Gahnite (ZnAl 2 O 4 ) belonging to the spinel family is known for its good thermal and optical properties and it is very suitable for doping with transition-metal ions such as Ni 2+ or Co 2+ [2] . Recently, transparent gahnite ceramics were fabricated [2] . In the present work, we report on the first transparent Cr 3+ -doped gahnite ceramics exhibiting intense and broadband emission in the red spectral range.