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.