Abstract

Tm doped materials are very attractive for highly efficient high power short pulse lasers in the wavelength range of two micrometer due to their broad gain bandwidths and the two-for-one pumping process with high power 800 nm laser diodes (LD). Among them, Tm doped sesquioxides (Tm:Re₂O₃, Re=Sc, Lu or Y) are among the most promising gain materials as they possess superior thermal and mechanical properties and broad gain bandwidth above 1980 nm where less H₂O absorption and Tm reabsorption exist. Pulses as short as 175fs, 218 fs and 148 fs were obtained previously by Ti³⁺:Al₂O₃ laser pumped saturable absorber mode-locked Tm³⁺:Lu₂O₃ [1], Tm³⁺:Sc₂O₃ [2] and Tm³⁺:LuScO₃ [3] lasers, respectively. Here, we demonstrate the first Kerr-lens mode-locked (KLM) Tm³⁺:Sc₂O₃ laser to our knowledge. It was in-band pumped by a 1611 nm Er:Yb fiber MOPA and generated pulses as short as 166 fs and 288fs at 440 mW and 1 W of average output power, respectively.

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