Emerald is a new broadly wavelength-tunable vibronic laser material with stimulated emission in the red to infrared due to
4
4 
transitions of Cr
3+. Emerald has gain from 12 050 cm
-1to 14 000 cm
-1with high gain from about 12 300 cm
-1to 13 700 cm
-1. An emerald laser oscillator has been achieved, but has high losses.