TiO2-SiO2 Nanocomposite Saturable Absorber for Ultrafast Photonics

A tapered microfiber decorated with titanium dioxide-silicon dioxide nanocomposite saturable absorber (TiO
₂
-SiO
₂
-SA) is demonstrated via alkali fusion method and spin-coating technique. The TiO
₂
-SiO
₂
-SA exhibited 17.1% modulation depth, 31.7 µJ/cm
²
saturation fluence and 35.4% non-saturable loss. The TiO
₂
-SiO
₂
-SA was able to generate a pulse duration of 797 fs at a repetition rate of 10.39 MHz and an average output power of 16.57 mW at 1.56 μm. This work presents an enhanced pulse duration within titanium-based saturable absorbers. The high damage threshold of beyond 24.82 GW/cm
²
and excellent stability are believed to have opened a new route of using nanomaterials derived from waste product for next generation ultrafast photonic applications.