Irradiation-Resistant Two-Dimensional W₂N₃ as Efficient Saturable Absorbers: Implications for Space Use

Area of Science:

• Materials Science
• Photonics
• Space Engineering

Background:

• Advanced antiradiation materials are crucial for space exploration.
• Nonlinear optical materials, like saturable absorbers (SAs), are vital for integrated photonics in space.
• Two-dimensional (2D) materials offer unique properties for such applications.

Purpose of the Study:

• To evaluate the space adaptability of 2D W2N3 under simulated space radiation.
• To investigate the radiation effects and damage mechanisms in W2N3 using advanced spectroscopic techniques.
• To assess the performance of W2N3 as a saturable absorber in a fiber laser system after irradiation.

Main Methods:

• Simulated space radiation exposure (60Co γ-ray irradiation).
• Femtosecond transient absorption spectroscopy to analyze carrier dynamics.
• Fabrication and testing of W2N3 nanosheets as saturable absorbers in a Yb-doped fiber laser.

Main Results:

• W2N3 retained robust third-order nonlinear saturable absorption after irradiation equivalent to over 45 years in low-Earth orbit.
• Femtosecond transient absorption spectra revealed detailed carrier dynamics and radiation effects.
• Irradiated W2N3 nanosheets performed identically to pristine ones as saturable absorbers in a Q-switched mode-locking Yb-doped fiber laser operating at ~1 μm NIR.

Conclusions:

• 2D W2N3 exhibits remarkable radiation resistance, making it suitable for space-based photonic applications.
• The material's nonlinear optical properties remain stable under significant radiation doses.
• W2N3 is a highly promising candidate for lasers, modulators, and other integrated photonic devices for space missions.