Crystal growth and a basic spectroscopic characterization of Prlt;supgt;3$+$lt;/supgt;-doped orthorhombic $-(Ylt;subgt;0.5lt;/subgt;Gdlt;subgt;0.5lt;/subgt;)Flt;subgt;3lt;/subgt; single crystals was performed. Laser operation on transitions in the green to the red spectral region could be demonstrated under InGaN laser diode excitation.