Pengchao Hu

Optical characterization of Tm3+ in LiYF4 and LiLuF4 crystals

A comparative study of the optical properties of Tm3+ in LiYF4 (YLF) and LiLuF4 (LLF) crystals is presented. Room temperature polarized absorption spectra and fluorescence spectra for Tm3+ in LYF and LLF were measured and analysed. By applying the Judd–Ofelt approach, the intensity parameters Ω2,4,6 were calculated. The radiative transition rates, branching ratios and radiative lifetimes were also obtained. The results were analysed and compared between these two samples, indicating that both of them are favourable laser media.

Optical spectroscopy of Nd3+ in LiLuF4 single crystals

The polarized absorption spectra, polarized fluorescence spectra and fluorescence decay curve of Nd3+ : LiLuF4 crystals are measured at room temperature. The peak absorption cross-sections are 6.944×10−20 cm2 and 1.664 × 10−20 cm2 at around 795 nm with full-width at half-maximum of 3.4 nm and 3.2 nm for π-polarization and σ-polarization, respectively. Based on Judd–Ofelt theory, the spectral parameters of Nd3+ in LiLuF4 crystals are investigated. The emission probabilities, branching ratio and radiative lifetime for the transitions from 4F3/2 are calculated. The radiative lifetime, fluorescence lifetime and quantum efficiency are 536 µs, 489 µs and 91%, respectively. Its spectroscopic parameters are also compared with those of some other important Nd3+-doped laser crystals.

Yb,Na:PbF 2 : a potential new high-power laser material

Yb:PbF(2) and Yb,Na:PbF(2) laser crystals are grown by the Bridgman method. Room-temperature absorption, photoluminescence spectra, and fluorescence lifetimes of Yb(3+) ions in the crystals have been investigated. Experimental results show that Na(+) ions codoping with Yb(3+) as charge compensators can suppress the deoxidization of Yb(3+) to Yb(2+). The result of diode-pumped laser operation of a Yb,Na:PbF(2) single crystal is reported for the first time to the best of our knowledge . With a 1mol.%Yb(3+)-doped sample, we obtained 2.37W output power at 1056nm for 17.9W of incident power at 978nm.

Optical properties of Tm, Mg:LiTaO3 laser crystal

A Tm, Mg co-doped LiTaO3 crystal has been grown by Czochralski method. Room temperature polarized absorption spectra and fluorescence spectrum of the Tm, Mg:LiTaO3 crystal were measured and analyzed. The maximum absorption cross-section is 6.0791 × 10−20 cm2 at around 790 nm with full width at half maximum of 5 nm. The emission cross-section of 3F4 manifold was 2.2 × 10−20 cm2. The spectroscopic parameters of Tm3+ ion were calculated by applying the Judd-Ofelt approach, and the intensity parameters Ω2, Ω4, and Ω6 were obtained to be 7.71 × 10−20, 1.09 × 10−20, and 1.16 × 10−20 cm2, respectively. The branching ratios and radiative lifetimes were also presented and the radiative lifetime of Tm3+3F4 → 3H6 transition is 968.3 μs. The results were also analyzed and compared with other Tm3+ doped hosts.

Optical characterization and evaluation of the laser properties of Yb3 + -doped (La, Sr)(Al, Ta)O3 single crystals

A Yb(3+)-doped mixed-perovskite single crystal (La, Sr)(Al, Ta)O(3) (LSAT) crystal is grown by the Czochralski method. The absorption spectrum, fluorescence spectrum and fluorescence lifetime of Yb(3+) ions have been investigated, and the spectroscopic parameters of Yb:LSAT have also been calculated. This crystal exhibits a remarkably large ground-state splitting (about 1100 cm(-1)), a relatively long fluorescence lifetime (0.85 ms) and broad absorption and emission bandwidths. The results indicate that the Yb(3+):LSAT crystal is a good candidate for diode-pumped ultrashort and tunable solid-state laser applications.

Crystal growth, spectral and laser properties of Nd:LSAT single crystal

Nd:(La, Sr)(Al, Ta)O3 (Nd:LSAT) crystal was grown by the Czochralski method. The absorption and fluorescence spectra of Nd:LSAT crystal at room temperature were investigated. With a fiber-coupled diode laser as pump source, the continuous-wave (CW) laser action of Nd:LSAT crystal was demonstrated. The result of diode-pumped laser operation of Nd:LSAT crystal single crystal is reported for what is to our knowledge the first time. The maximum output power at 1064 nm was obtained to be 165 mW under the incident pump power of 3 W, with the slope efficiency 10.9%.