Mode-Locked Operation of Yb:LuGG Channel Waveguide Laser Using Carbon Nanotubes

Waveguide (WG) lasers fabricated by the femtosecond direct laser writing technique (fs-DLW) within laser gain media have been considered as a promising laser platform, providing tightly confined and long-propagating laser beams inside the WG [1]. Among the laser host crystals, the gallium garnet family crystals (Yb:RE<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>Ga<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</inf>, RE = Lu, G, Y) are notable for their stable structure, high optical quality, and excellent thermal characteristics [2]. The combination of their superior thermal conductivity and the high Stokes efficiency of trivalent ytterbium (Yb) ion dopants leads to a reduction of thermal load on the host material. Additionally, arc-discharged single-walled carbon nanotube (SWCNT)-based saturable absorbers (SAs) are widely employed as passive switching devices in various pulsed laser operations due to their flexible fabrication process and ease of integration into desired optical devices [3]. In this work, we introduce the mode-locked operation of fs-DLW Yb:Lu<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>Ga<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</inf> (Yb:LuGG) WG laser utilizing SWCNTs as a mode-locker.