Sb₂Te₃ thin film for the passive Q-switching of a Tm:GdVO₄ laser

Abstract

We report on the first application of an antimony telluride (Sb2Te3) thin film as a saturable absorber (SA) in a microchip laser. The 3–15 nm-thick Sb2Te3 films were deposited on glass substrates by pulsed magnetron sputtering and they were studied by SEM, X-ray diffraction, Raman and optical spectroscopy. The saturable absorption of the Sb2Te3 film was confirmed at 1.56 μm for ns-long pulses revealing low saturation intensity of 0.17 MW/cm2. The microchip laser was based on a Tm:GdVO4 crystal diode-pumped at ~802 nm. In the continuous-wave regime, this laser generated 3.54 W at 1905–1921 nm with a slope efficiency of 37%. The Q-switched laser generated a maximum average output power of 0.70 W at 1913 nm. The highest pulse energy of 3.5 µJ and the shortest pulse duration of 223 ns were obtained at the 200 kHz repetition rate.