Growth and Characterization of Yb: CALYGLO Crystal for Ultrashort Pulse Laser Applications

Abstract

Yb:CALYGLO crystals with a dopant concentration of 5 at.% were successfully grown using the Czochralski method. The crystal samples were extensively studied to analyze their structure, room temperature and low temperature spectra, and laser properties. The highest absorption cross-section at 977 nm was calculated to be 1.83 × 10−20 cm2 for σ polarization and 5.32 × 10−20 cm2 for π polarization. Similarly, the emission cross-section was determined to be 1.38 × 10−20 cm2 at 980 nm for σ polarization and 2.28 × 10−20 cm2 at 981 nm for π polarization, with a full width at half maximum (FWHM) of 50.3 nm and 89.5 nm, respectively. The fluorescence lifetime of the 5 at.% Yb:CALYGLO crystal at 2F5/2 was measured to be 1.10 ms. Additionally, gain cross-sections were calculated for different β values. In the continuous laser experiment, the crystal demonstrated a laser output of 20.15 W at 1057 nm, with a slope efficiency of 53.3%. These experimental findings indicate that the lattice of Y3+ in the crystal is partially replaced by Lu3+ and Gd3+, resulting in a broader spectrum. Consequently, this crystal shows promising potential as a gain medium for ultrashort pulse laser crystals.

Growth, Structure, and Spectroscopic Properties of a Disordered Nd:SrLaGaO4 Laser Crystal

“…Ultrafast and tunable lasers show extensive applications in intelligent processing [1], communication and remote sensing [2], national defense and military [3], medical beauty, and scientific research [4] because of the high pulse energy, high peak power, and short duration. In recent years, crystals with disordered structures have attracted extensive attention for ultrafast and tunable lasers gain media due to the wide emission band [5][6][7][8]. The random distribution of cations with different valences in the same lattice position leads to the disordered distribution of the lattice field, which leads to the uneven broadening of absorption and emission spectra [9,10].…”

“…The ABCO 4 family crystallizes in the K 2 NiF 4 tetragonal structure with a space group of I 4 /mmm, has a complex and disordered lattice field, which causes a large inhomogeneous broadening of absorption and emission spectra. In general, rare-earth-doped CaYAlO 4 , CaGdAlO 4 , and SrLaAlO 4 laser crystals have been widely studied in ultrafast and tunable laser fields [7,9,15,[21][22][23][24]. In 2016, Liu et al reported a stable 458 femtosecond continuouswave mode-locked pulse in the Nd:SrLaAlO 4 crystal at 1077.9 nm with an average power output of 520 mW [21].…”