Wavelength shift with a diode-pumped continuous-wave Yb:CALGO laser

Abstract

The dependence of an emission wavelength on the crystal temperature was first investigated for a diode-pumped continuous-wave Y b 3 + -doped C a G d A l O 4 (Yb:CALGO) laser. A maximum output power of 11 W was obtained, corresponding to a slope efficiency of 19.8%. The output wavelength varied from 1051.10 nm to 1054.72 nm with increased absorbed pump power. This wavelength shift is attributed to a change in the crystal temperature. This observation is, to our best knowledge, an original conclusion about this phenomenon in a Yb:CALGO laser. We use a temperature-dependent model to explain the emission wavelength shifts that can be generalized to any such quasi-three-level materials.

Advances of Yb:CALGO Laser Crystals

“…This advantage also contributes to the broadening phenomenon. Additionally, the great thing for Yb: CALGO is that it not only possesses the aforementioned broadening effect, but also shows excellent stability because those two substitute ions (Yb 3+ , 70 and Gd 3+ , 64) have trivial mass difference compared with Yb 3+ (70) and Ca 2+ (20) [37]. The lattice dimensions of Yb:CALGO are usually determined by X-ray diffraction method and the typical results carried out by Talik et al recently are shown in Table 1 [38].…”

“…It is noteworthy that the wavelength spacing changed from 2.16 nm to 41.44 nm by rotating the BRF and the output power was as high as~7.5 W for 25 W of the incident pump power. In addition, as for single-wavelength tunability, Liang's group studied the dependence of emission wavelength on the crystal temperature [70]. They first observed that by increasing absorbed pump power, the temperature of the Yb:CALGO crystal also increased, which led to the output wavelength variation from 1051.10 nm to 1054.72 nm.…”