2 μm solid-state laser mode-locked by single-layer graphene

We report a 2 lm ultrafast solid-state Tm : Lu 2 O 3 laser, mode-locked by single-layer graphene, generating transform-limited $410 fs pulses, with a spectral width $11:1 nm at 2067 nm. The maximum average output power is 270 mW, at a pulse repetition frequency of 110 MHz. This is a convenient high-power transform-limited ultrafast laser at 2 lm for various applications, such as laser surgery and material processing.