AUTHOR=Zhang Yani , Ling Weijun , Qiao Dun , Sun Rui , Chen Chen 

TITLE=Passively Q-Switched Mode-Locked Tm,Ho:CaYAlO4 Laser Based on Double-Walled Carbon Nanotube Saturable Absorber

JOURNAL=Frontiers in Physics

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2020.00086

DOI=10.3389/fphy.2020.00086

ISSN=2296-424X

ABSTRACT=<p>A passively Q-switched mode-locked (QML) operation in Tm,Ho:CaYAlO<sub>4</sub> bulk laser was demonstrated experimentally by employing double-walled carbon nanotubes (DWCNTs) as a saturable absorber. The laser is pumped by a self-made wavelength tunable Ti:sapphire laser, and the pump threshold of Tm,Ho:CaYAlO<sub>4</sub> laser was measured at 677 mW using transmittance of 1.5% output coupler. A stable QML operation state was achieved when the absorption pumping power reached 1,958 mW. When the pumping power reached 2.6 W, the maximum output power was 64 mw with a central wavelength of 2,085 nm, the corresponding repetition frequency of mode-locked pulse was 98.04 MHz, and the modulation depth in Q-switching envelopes is close to 100%.</p>