Deactivation effects of the lowest excited state of Ho^3+ at 29 μm emission introduced by Pr^3+ ions in LiLuF_4 crystal

Abstract

The use of Pr3+ codoping for enhancement of the Ho3+:5I6 →5I7 mid-IR emissions were investigated in the LiLuF4 crystal for the first time. It was found that Pr3+ greatly increased Ho3+ 2.9 μm emission by depopulating the Ho3+:5I7 level while having little influence on the Ho3+:5I6 level, leading to greater population inversion. The energy transfer efficiency from Ho3+:5I7 to Pr3+:3F2 is calculated to be 88%. Based on Judd-Ofelt theory, the 2.9 μm emission cross section is calculated to be 1.91×10(-20) cm2, and the gain property of the Ho3+:5I6 →5I7 transition is discussed. We propose that the Ho, Pr:LiLuF4 crystal may be a promising material for 2.9 μm laser applications.

Enhanced emission of 286 μm from diode-pumped Ho^3+/Yb^3+-codoped PbF_2 crystal

“…It is well know that Ho 3+ is a natural candidate for ∼3 µm lasers owing to the 5 I 6 → 5 I 7 transition [6,7]. However, the ∼3 µm laser operation cannot be obtained efficiently due to (i) the lack of commercialized laser diodes (LD) corresponding to the intrinsic absorption of Ho 3+ ions, and (ii) the population bottleneck effect that occurs with the 5 I 6 → 5 I 7 transition which is a self-terminated transition.…”

Spectroscopic properties of Ho3+-doped PbF2 single crystal for 2μm lasers

“…It is well know that Ho 3+ is a natural candidate for $2 lm lasers owing to the 5 I 7 ? 5 I 8 transition [8][9][10]. However, the $2 lm laser operation cannot be obtained efficiently due to the lack of commercialized laser diodes (LD) corresponding to the intrinsic absorption of Ho 3+ ions.…”

Growth and optical characterization of Ho3+ doped PbF2 single crystal

“…The host material for MIR lasers is expected to possess low phonon energy, minimal absorption coefficient in the H 2 O absorption band at 3 µm, and high radiative emission rates. Compared with oxide crystals, fluoride crystals have several advantages, for instance low phonon energy, which reduces non-radiative relaxation between adjacent energy levels; lower refractive index, which reduces the effect of nonlinear thermo optic effects arising in intense laser pump; and longer fluorescence lifetime, which improves energy storage [2]. We are now focusing our scientific program on a new potential gain medium ∼β-PbF 2 crystal for efficient laser operation, which has high thermal conductivity (28 W/m/K) [3], low phonon energy, and potential interest for laser applications [4].…”