Broadband Nonlinear Photoresponse of 2D TiS₂ for Ultrashort Pulse Generation and All‐Optical Thresholding Devices

TLDR

2D titanium disulfide (TiS₂) shows strong light absorption from visible to infrared, making it attractive for nonlinear photonics, yet the broadband light–matter interaction mechanism remains unclear and devices are undeveloped. This study reports experimental evidence for the broadband nonlinear photoresponse mechanism in ultrathin TiS₂ nanosheets (400–1390 nm) using laser Z‑scan measurements. Laser Z‑scan measurements were employed to probe the nonlinear photoresponse of the nanosheets across the 400–1390 nm range. The TiS₂‑based saturable absorber fabricated on a fiber generated 1.04 ps pulses at 1569.5 nm and increased the pulse SNR from 1.90 to 10.68 dB, demonstrating high‑performance nonlinear photonic devices for telecom applications.

Abstract

Abstract 2D titanium disulfide (TiS 2 ) is recently found to have strong light absorption properties from visible to infrared (IR) region. This feature is highly attractive for applications in nonlinear photonics; however, the mechanism of broadband light–matter interaction is yet to be determined and nonlinear photonic devices are not developed. Here, for the first time, the experimental evidence supporting the mechanism of the broadband nonlinear photoresponse in ultrathin TiS 2 nanosheets ranging from 400 nm to 1390 nm is reported through laser Z ‐scan measurements. High‐performance nonlinear photonic devices operating in the telecommunication band are also demonstrated. A novel saturable absorber (SA) device is successfully fabricated based on a 2D TiS 2 ‐decorated fiber, which exhibits outstanding ultrashort pulse generation performance with pulse duration of ≈1.04 ps centered at 1569.5 nm. Furthermore, as a stable all‐optical thresholding component, the device can effectively attenuate noise and boost the signal‐to‐noise ratio of the pulse from 1.90 to 10.68 dB. The findings indicate that TiS 2 ‐based SA devices can be developed into excellent highly nonlinear photonic devices, which may advance the development of TiS 2 ‐based optical communication technologies in the future.