Novel disordered Nd3+:Ca(Gd0.5Y0.5)Al3O7 melilite crystal: growth, spectroscopic properties, continuous wave and tunable laser performance

Abstract

A novel Nd³⁺:Ca(Gd_0.5Y_0.5)Al₃O₇ melilite (Nd:CGYAM) crystal was designed and successfully grown. The structure and spectroscopic properties of the as-grown Nd:CGYAM crystal were investigated systematically. The lattice parameters of the Nd:CGYAM crystal are calculated to be a = b = 7.70584 Å, c = 5.06356 Å. The maximum phonon energy of the crystal is estimated as 767.7 cm⁻¹. Absorption spectrum shows the absorption cross-section is 2.09 × 10^-20 cm² at 809 nm in the Nd:CGYAM crystal, and its FWHM reaches 20.6 nm. The radiative lifetime of Nd³⁺:⁴F_3/2 level is 295.46 µs obtained by J-O analysis. The emission cross-section of the Nd:CGYAM crystal is 4.85 × 10^-20 cm² at 1062 nm, with a FWHM of 13.5 nm. The fluorescence lifetime of Nd³⁺:⁴F_3/2 level is fitted as 270.30 µs. Laser operation was conducted to study the laser performance of the Nd:CGYAM crystal. The maximum output power is 1.181 W, with a slope efficiency of 25.5 % and central wavelength of 1061.16 nm. Tunable laser operation shows the tunable range of the Nd:CGYAM crystal is separated into two segments, the first segment is 1059.22 nm – 1069.39 nm and the second one ranges from 1076.66 nm to 1081.02 nm. To the best of our knowledge, this is the first time to realize continuous wave and tunable laser output in Nd:CGYAM crystal. Summarizing the results above, the Nd:CGYAM crystal is proved to be a promising material candidate for ∼ 1.06 µm tunable laser applications.