Optical gain in Er3+-doped transparent LuVO4 crystal at 850 nm

Evidence of a positive optical gain has been observed in an Er3+-doped LuVO4 crystal in a pump and probe experiment. The radiative transition from the S-4(3/2) (H-2(11/2)) level to the I-4(13/2) metastable level of the Er3+ ion gives rise to an intense emission centred at 850 nm. The S-4(3/2)(H-2(11/2)) level of Er3+ ions is populated with high power laser pulses at 532 nm due to the I-4(15/2) -> S-4(3/2)(H-2(11/2)) ground state absorption. The S-4(3/2)(H-2(11/2)) -> I-4(13/2) electronic transition is stimulated with a low signa cw beam at 850 nm. Under these conditions, the high power pump Pulses allowed to reach the population inversion necessary between the Er3+ levels of the transition S-4(3/2) (H-2(11/2)) -> I-4(13/2). An increase of the emission intensity of the sample is observed at the signal wavelength, due to the stimulated emission. Positive optical gain around 2 cm(-1) (8.6 dB/cm) has been measured in Er3+-doped LuVO4 crystal. (C) 2009 Elsevier B.V. All rights reserved.