Structure and nonlinear optical properties of novel transparent glass-ceramics based on Co²⁺:ZnO nanocrystals

Abstract

Transparent glass-ceramics (GCs) based on Co 2+ :ZnO nanocrystals (mean diameter, 11 nm) are synthesized on the basis of cobalt-doped glasses of the K 2 O-ZnO-Al 2 O 3 -SiO 2 system. For these GCs, the absorption band related to the 4 A 2 ( 4 F) → 4 T 1 ( 4 F) transition of Co 2+ ions in tetrahedral sites spans until ~1.73 μm. Saturation of the absorption is demonstrated at 1.54 μm, with a saturation fluence F s = 0.8 ± 0.1 Jcm −2 (σ GSA = 1.7 ± 0.2 × 10 −19 cm 2 ) and a recovery time of 890 ± 10 ns. Passive Q-switching of an Er,Yb:glass laser is realized with the synthesized GCs. This laser generated 0.37 mJ/100 ns pulses at 1.54 μm. The developed GCs are promising as saturable absorbers for 1.6-1.7 μm crystalline erbium lasers.

Oriented zinc oxide nanorods: A novel saturable absorber for lasers in the near-infrared

“…The absorption saturation experiment performed at 1.560 µm revealed a saturation intensity as low as 16 kW/cm 2 for this material [ 26 ]. Loiko et al studied the saturable absorption of Co 2+ -doped ZnO nanocrystals in a glass matrix at 1.540 µm, employing them as a SA for a bulk Er laser [ 27 ], however, the saturable absorption was mostly due to the Co 2+ ions in T d sites.…”

Compact 0.7 mJ/11 ns eye-safe erbium laser

“…Recently, transparent glass-ceramics (GCs) containing various Co 2+ -doped nanocrystals, e.g. MgAl 2 O 4 [14], ZnAl 2 O 4 [15], γ-Ga 2 O 3 [16], and ZnO [17], have been studied for the replacement of single crystalline SAs. The GCs are synthesized by a cost-effective melt-quenching method with subsequent heat-treatments and possess good optical homogeneity [14,15].…”