Few-layered α-Fe2O3 nanoflake saturable absorber for stable MIR pulse generation

Abstract

Hematite (α-Fe2O3), as one of the most prevalent transition metal oxides (TMOs) on the Earth, has been the hot spot of intense research for recent decades. Understanding the optical signatures in hematite is essential for the design of α-Fe2O3-based devices in the photoelectrochemical and photonic fields. In the present work, we successfully synthesized hematite nanoflakes by the facile oil bath method. The small signal transmission of the prepared few-layered hematite nanoflakes was 76% and the modulation depth was determined as 11.2%. Subsequently, the α-Fe2O3 nanoflakes were successfully implemented as the saturable absorber in a passively Q-switched Tm:YLF laser around 2 µm. The achieved shortest pulse duration was 293 ns. The long-term pulse-pulse fluctuation was < 3% in root-mean square error (RMSE), indicating the Q-switching pulses are highly stable. The present work will assist in understanding the nonlinear optical features and their interpretation in stable Q-switching pulses generation.