Demonstration of laser cooling in a novel all oxide GAYY silica glass
Jyothis Thomas, Thomas Meyneng, Amirhossein Tehranchi, Nicolas Grégoire, Frédéric Monet, Denis V. Seletskiy, Younès Messaddeq, Raman Kashyap
Abstract
Abstract We demonstrate laser induced cooling in ytterbium doped silica (SiO 2 ) glass with alumina, yttria co-doping (GAYY-Aluminum: Yttrium: Ytterbium Glass) fabricated using the modified chemical vapour deposition (MCVD) technique. A maximum temperature reduction by − 0.9 K from room temperature (296 K) at atmospheric pressure was achieved using only 6.5 W of 1029 nm laser radiation. The developed fabrication process allows us to incorporate ytterbium at concentration of 4 × 10 26 ions/m 3 which is the highest value reported for laser cooling without clustering or lifetime shortening, as well as to reach a very low background absorptive loss of 10 dB/km. The numerical simulation of temperature change versus pump power well agrees with the observation and predicts, for the same conditions, a temperature reduction of 4 K from room temperature in a vacuum. This novel silica glass has a high potential for a vast number of applications in laser cooling such as radiation-balanced amplifiers and high-power lasers including fiber lasers.