Third-order optical nonlinearities of NbC MXene and its application as an ultra-broadband mode-locker

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 12; no. 3; pp. 893 - 92
• Main Authors: Lee, Kyungtaek, Kwon, Suh-young, Choi, Jaehak, Kim, Jeehwan, Woo, Taeho, Ryu, Janghyun, Jung, Junha, Lee, Ju Han
• Format: Journal Article
• Published: 18.01.2024
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/d3tc03048b

MXenes have been one of the most extensively investigated nonlinear optical materials at short-wave infrared (SWIR) wavelengths. Herein, we systemically investigated the electronic and optical characteristics of Nb 4 C 3 MXene. First, the electronic and linear optical properties of Nb 4 C 3 MXene were theoretically estimated using density functional theory calculation, thereby revealing the metallic property of Nb 4 C 3 MXene. Through Z-scan measurements, we observed large saturable absorption of Nb 4 C 3 MXene at 1560 and 1910 nm wavelengths. Self-focusing and self-defocusing properties were also observed at 1560 and 1910 nm wavelengths, respectively. The effective nonlinear absorption coefficient and nonlinear refractive index of Nb 4 C 3 MXene were estimated as −(2.27 ± 0.12) × 10 3 cm GW −1 and (1.3 ± 0.04) × 10 −2 cm 2 GW −1 at 1560 nm, and −(2.73 ± 0.08) × 10 4 cm GW −1 and −(0.80 ± 0.01) × 10 −1 cm 2 GW −1 at 1910 nm. Based on the large and broadband optical nonlinearities, a single broadband saturable absorber (SA) was fabricated to generate optical pulses at SWIR wavelengths. Stable mode-locked pulses 1.66 ps at 1559.8 nm and 1.62 ps pulse duration at 1930.3 nm were generated with a single Nb 4 C 3 MXene-based SA when incorporated in an erbium-doped fiber ring laser cavity and a thulium holmium-doped fiber cavity, respectively. This work indicates that Nb 4 C 3 MXene can be a high-performance material platform for broadband optical devices at SWIR or broader wavelengths. The broadband nonlinear optical properties of Nb 4 C 3 MXene were investigated using Z-scan techniques. Using Nb 4 C 3 MXene, a single saturable absorber operating at both 1560 and 1930 nm was successfully fabricated for fiber laser mode-locking.