Watt-level femtosecond Tm-doped “mixed” sesquioxide ceramic laser in-band pumped by a Raman fiber laser at 1627 nm
Ning Zhang, Zhanxin Wang, Shande Liu, Wei Jing, Hui Huang, Zixuan Huang, Kangzhen Tian, Zhiyong Yang, Yongguang Zhao, Uwe Griebner, Valentin Petrov, Weidong Chen
Abstract
We report on a semiconductor saturable absorber mirror mode-locked Tm:(Lu,Sc) 2 O 3 ceramic laser in-band pumped by a Raman fiber laser at 1627 nm. The nonlinear refractive index ( n 2 ) of the Tm:(Lu,Sc) 2 O 3 ceramic has been measured to be 4.66 × 10 −20 m 2 /W at 2000 nm. An average output power up to 1.02 W at 2060 nm is achieved for transform-limited 280-fs pulses at a repetition rate of 86.5 MHz, giving an optical efficiency with respect to the absorbed pump power of 36.4%. Pulses as short as 66 fs at 2076 nm are produced at the expense of output power (0.3 W), corresponding to a spectral bandwidth of 69 nm. The present work reveals the potential of Tm 3+ -doped sesquioxide transparent ceramics for power scaling of femtosecond mode-locked bulk lasers emitting in the 2-µm spectral range.