Passively mode-locked 2-μm Tm：YAP laser with a double-wall carbon nanotube absorber

We report on a diode-pumped passively continuous wave(cw) mode-locked Tm:YAP laser with a double-wall carbon nanotube(DWCNT) absorber operating at a wavelength of 2023 nm for the first time,to the best our knowledge.The DWCNT absorber is fabricated on a hydrophilic quartz substrate by using the vertical evaporation technique.The output power is as high as 375 mW.A stable pulse train with a repetition rate of 72.26 MHz is generated with a highest single pulse energy of 5.2 μJ.