Thickness- and Wavelength-Dependent Nonlinear Optical Absorption in 2D Layered MXene Films

Area of Science:

• Materials Science
• Optics and Photonics
• Nanotechnology

Background:

• MXenes are a rapidly expanding family of 2D materials with significant research interest.
• Nonlinear optical absorption (NOA) is crucial for advanced photonic applications.
• Ti3C2Tx MXene films offer tunable properties for optoelectronic devices.

Purpose of the Study:

• To investigate the nonlinear optical absorption (NOA) properties of Ti3C2Tx MXene films.
• To explore the layer-dependent and power-dependent NOA behavior.
• To assess the potential of MXene films in nonlinear photonic devices.

Main Methods:

• Developed a transfer-free, layer-by-layer film coating method for MXene films.
• Utilized the Z-scan technique to characterize NOA at ~800 nm.
• Integrated MXene films onto silicon nitride waveguides for characterization at ~1550 nm.

Main Results:

• Ti3C2Tx MXene films exhibit strong, layer-dependent NOA.
• NOA transitioned from reverse saturable absorption (RSA) to saturable absorption (SA) as layer number increased from 5 to 30 at ~800 nm.
• Nonlinear absorption coefficient (β) varied significantly, showing power-dependent trends and different behavior at ~1550 nm.

Conclusions:

• 2D Ti3C2Tx MXene films possess intriguing and tunable nonlinear optical properties.
• The layer-dependent NOA behavior highlights their versatility for photonic applications.
• MXene films show promise for implementing high-performance nonlinear photonic devices.