Zirconium pentatelluride saturable absorber for solid-state ultrafast lasers

Abstract

The application of two-dimensional (2D) materials as saturable absorbers (SAs) in ultrafast solid-state lasers has become a research hotspot due to its broadband absorption properties and simple fabrication process. However, the development of ultrafast solid-state lasers based on 2D material SAs is not mature, especially for mid infrared wavelengths. In this paper, the morphology and optical properties of zirconium pentatelluride (ZrTe5) are characterized. Using ZrTe5 as SAs, the picosecond continuous wave mode-locked (CWML) pulses with repetition frequencies of tens of MHz are obtained at 1 nm, 1.3 nm and 2 nm, respectively. The corresponding spectral centers are 1065.6 nm, 1343.3 nm and 2014.3 nm, respectively. For the 3 nm ultrashort laser, a passively mode-locked solidstate laser based on two-dimensional materials is realized for the first time, and a passively Q-switched mode-locked pulse with a pulse width of 800 ps and a repetition frequency of 180 MHz is obtained. Our results demonstrate the excellent modulation effect and great application potential of ZrTe5 in solid-state ultrafast lasers, which also proves the broadband absorption characteristics of ZrTe5.