Two-Dimensional Bismuthene Showing Radiation-Tolerant Third-Order Optical Nonlinearities

Abstract

The ever-increasing space exploration enterprise calls for novel and high-quality radiation-resistant materials, among which nonlinear optical materials and devices are particularly scarce. Two-dimensional (2D) materials have shown promising potential, but the radiation effects on their nonlinear optical properties remain largely elusive. We previously fabricated 2D bismuthene for mode-locking sub-ns laser; herein, their space adaption was evaluated under a simulated space radiation environment. The as-synthesized thin layers of bismuthene exhibited strong third-order nonlinear optical responses extending into the near-infrared region. Remarkably, when exposed to 60Co γ-rays and electron irradiation, the bismuthene showed only slight degradation in saturable absorption behaviors that were critical for mode-locking in space. Ultrafast spectroscopy was applied to address the radiation effects and damage mechanisms that are difficult to understand by routine techniques. This work offers a new bottom-up approach for preparing 2D bismuthene, and the elucidation of its fundamental excited-state dynamics after radiation also provides a guideline to optimize the material for eventual space applications.

Defect Engineering of Ultrathin WO3 Nanosheets: Implications for Nonlinear Optoelectronic Devices

“…The observed photoinduced bleaching and absorption dynamics accounted for the saturable absorption of the 2D metal oxides. With the excitation photon energy (532 nm, 2.33 eV) being larger than or equal to the metal oxide band gaps, electrons jumped from the VB to the CB within a few femtosecond but further photoabsorption was prevented at high pump intensity due to Pauli blocking and resulted in saturable absorption, , which was also substantiated by the long exciton bleaching time on the μs timescale. Meanwhile, the longer excited-state absorption time of D-WO 3 (336 ps) than that of WO 3 (162 ps) at 1200 nm well explained the enhanced saturable absorption of the former (Table S3).…”

Ultrafast Generation of Coherent Phonons in Two-Dimensional Bismuthene

“…Bimuthene is a newly reported 2D quantum material by us and other groups, which has exhibited promising potential use in nonlinear optics, topological materials, and catalysis. − Although the generation of optical phonons in bulk Bi films had been previously reported, studies on the coherent phonon modulation in 2D Bi with quantum confinement effect are rather scant. − In this work, we managed to generate size-dependent phonon coherence of bulk Bi, multi-layer Bi, and few-layer Bi by an ultrafast femtosecond laser pulse and made a systematic comparison thorough a combination of computation, femtosecond transient absorption, and reflectance spectroscopic methods. The results showed that with the decrease of the thickness of Bi materials, the carrier excited by a femtosecond ultrafast laser became more difficult to transfer and the chemical bond was softened, inducing shortened decoherence time and red-shifted vibration frequency.…”

“…We previously developed various methods including liquid exfoliation and bottom-up chemical synthesis for 2D bismuthene fabrication. , Herein the one prepared with the chemical synthesis method was used for investigation of phonon dynamics. The schematic layered structures of the three Bi materials with distinct thicknesses shown in the insets of Figure a–c imply the evolution of bismuth from bulk (named bulk Bi) to multiple layers (named multilayer Bi) and finally to the few layers (named few-layer Bi).…”

Synthesis, Structures and Optical Limiting of Catecholato‐Based Aluminum Oxo Clusters

“…Third‐order nonlinear optical (NLO) materials have received extensive attention due to their application in optical switches, radiation‐resistant materials and optical limiting [50–53] . Traditional inorganic and organic materials have been widely studied for their favorable NLO properties [54–57] .…”