Growth and Spectral Properties of Er3+:LiYF4 Single Crystal

Er3+: LiYF4 single crystal was grown by the Bridgman method under non-vacuum atmosphere. The single crystal was in size of phi 9mmx68mm with 1mol% concentration of Er3+ ions. Optical properties of the single crystal including the refractive index, UV and IR transmission spectra, absorption spectrum, near-infrared emission spectrum under 980nm excitation and mid-infrared emission spectrum under 792nm excitation were measured. The intensity parameters (Omega(t), t=2,4,6), oscillator strength(f(cal)), transition probabilities (A), branching ratios (beta) and radiation lifetimes (tau(rad)) of Er3+ ions in the LiYF4 were estimated by using the Judd-Ofelt theory. The near-and mid-infrared fluorescence properties of the sample were discussed. The results indicate that near infrared fluorescence at 1.5 mu m corresponding to the Er3+: I-4(13/2)-> I-4(15/2) transition is observed under 980nm excitation while mid-infrared fluorescence at 3.0 mu m corresponding to the Er3+:I-4(11/2)-> I-4(13/2) transition is detected under 792 nm excitation. The reason that caused the weakening of fluorescence at 3.0 mu m is analyzed.