Mode-locked operation in thulium-holmium doped fiber laser based on Cr₂AlC MAX phase SA coated arc-shaped fiber

This study presents the application of MAX phase material as a mode-locker in the thulium-holmium-doped fiber laser (THDFL) cavity in generating ultrashort pulses. MAX phase materials were rapidly developed for applications in the pulsed laser field due to their promising properties and characteristics, such as strong nonlinear absorption, high damage tolerance, and good thermal and electrical conductivities. Chromium Aluminum Carbide (Cr₂AlC) MAX phase sample was explicitly introduced into the cavity by drop-casting the Cr₂AlC onto the fabricated arc-shaped fiber. As a result, an ultrafast mode-locking laser system was achieved utilizing a Cr₂AlC saturable absorber (SA) at a pump power of 115.8 mW, having a central wavelength of 1908.58 nm. The spectral bandwidth obtained was 3 nm, and a measured pulse repetition rate and pulse width of 12.14 MHz and 1.3 ps, respectively. The results indicate that Cr₂AlC SA is a promising material to be used as a passive SA to initiate the mode-locking generation of fiber laser in the 1.9 μm band.