Intensity-dependent nonlinear refraction of antimonene dispersions in the visible and near-infrared region

Covalently Silane-Functionalized Antimonene Nanosheets and Their Copolymerized Gel Glasses for Broadband Vis-NIR Optical Limiting

Two-dimensional antimonene has many potential applications for its high mobility, high stability, and tunable band gap. The covalent chemistry of antimonene and the molecular doping or hybrid of antimonene remain incomplete for further applications. In this work, silane-functionalized antimonene nanosheets and their copolymerized organically modified silicate gel glasses are designed and prepared. The experimental data confirmed that 3-glycidoxypropyltrimethoxysilane interacts covalently with antimonene. Compared with unfunctionalized antimonene, the silane-functionalized antimonene shows higher concentration, higher compatibility, and dispersion stability in solvents and gel matrices. In particular, the doping concentration of functionalized antimonene nanosheets can reach 2% in gel glass, which is larger than conventional nanocomposites and nanohybrids. These nanosheets exhibit outstanding optical limiting performance in the visible and long-wavelength near-infrared regions (532-2150 nm). The mechanism of optical limiting is found to be a combination of nonlinear absorption, nonlinear refraction, and nonlinear scattering. The silane-functionalized antimonene nanosheets and their copolymerized hybrids will be promising materials for optoelectronics, biology, energy, and others.

Two-Dimensional Antimony Oxide

Two-dimensional (2D) antimony, so-called antimonene, can form antimonene oxide when exposed to air. We present different types of single- and few-layer antimony oxide structures, based on density functional theory (DFT) calculations. Depending on stoichiometry and bonding type, these novel 2D layers have different structural stability and electronic properties, ranging from topological insulators to semiconductors with direct and indirect band gaps between 2.0 and 4.9 eV. We discuss their vibrational properties and Raman spectra for experimental identification of the predicted structures.

Kerr Nonlinearity in germanium selenide nanoflakes measured by Z-scan and spatial self-phase modulation techniques and its applications in all-optical information conversion

Germanium selenide (GeSe) has attracted considerable research interest due to its unique photoelectric characteristics: high abundance occurrence, low toxicity, high stability, and environmentally sustainable. To the best of our knowledge, less literature is available on the nonlinear optical (NLO) properties of GeSe and on its significance of the electronic structure. In this work, the GeSe nanoflake ethanol suspensions have been studied by using liquid phase exfoliation method and then characterized by Raman, transmission electron microscopy (TEM), transmittance and atomic force microscopy (AFM). The NLO properties of GeSe suspensions with different concentration are investigated by Z-scan and spatial self-phase modulation (SSPM) methods with continuous wave laser, which are coherent with the parameter nonlinear refractive index n2 and the third order nonlinear polarizabilities χ⁽³⁾. The nonlinear refractive index n2 of GeSe dispersions basically occur in the order of 10^-9 cm²/W for Z-scan methods and 10^-6 cm²/W for SSPM technique, whereas the third-order nonlinear polarizabilities χ⁽³⁾ _total are within the range of 10^-6 esu for SSPM method. On the basis of these substantial characteristics of the NLO response and high stability of the 2D GeSe, we have experimentally studied the applications of the GeSe suspensions on all-optical information conversion technique.

Emerging 2D materials beyond graphene for ultrashort pulse generation in fiber lasers

Ultrafast fiber lasers have significant applications in ultra-precision manufacturing, medical diagnostics, medical treatment, precision measurement and astronomical detection, owing to their ultra-short pulse width and ultra-high peak-power. Since graphene was first explored as an optical saturable absorber for passively mode-locked lasers in 2009, many other 2D materials beyond graphene, including phosphorene, antimonene, bismuthene, transition metal dichalcogenides (TMDs), topological insulators (TIs), metal-organic frameworks (MOFs) and MXenes, have been successively explored, resulting in rapid development of novel 2D materials-based saturable absorbers. Herein, we review the latest progress of the emerging 2D materials beyond graphene for passively mode-locked fiber laser application. These 2D materials are classified into mono-elemental, dual-elemental and multi-elemental 2D materials. The atomic structure, band structure, nonlinear optical properties, and preparation methods of 2D materials are summarized. Diverse integration strategies for applying 2D materials into fiber laser systems are introduced, and the mode-locking performance of the 2D materials-based fiber lasers working at 1-3 μm are discussed. Finally, the perspectives and challenges facing 2D materials-based mode-locked fiber lasers are highlighted.

2D group-VA fluorinated antimonene: synthesis and saturable absorption

A new derivative of antimonene named fluorinated antimonene was synthesized using the method of ionic liquid-assisted electrochemical exfoliation and synchronous fluorination. Passive Q-switched pulses were produced from a Nd:LuAG laser with fluorinated antimonene, having a pulse width of 326.7 ns and a repetition rate of 733.1 kHz demonstrating its potential application as a saturable absorber. Density functional theory calculations revealed that compared with pure antimonene with an indirect bandgap, fluorinated antimonene exhibits a direct bandgap modulated by the fluorination degree showing that fluorinated antimonene would be applied as optical devices beyond its application as a saturable absorber.

Structure dependent optoelectronic properties of monolayer antimonene, bismuthene and their binary compound

The absorption spectra of antimonene, bismuthene, and their BiSb binary compound are revealed.