Angle-selective perfect absorption with two-dimensional materials.

Area of Science:

• Photonics and optoelectronics
• Materials science
• Nanotechnology

Background:

• Two-dimensional (2D) materials offer significant potential for photonic and optoelectronic devices.
• Weak light absorption in 2D materials currently limits their practical applications.
• Developing strategies to enhance light absorption is crucial for advancing 2D material-based technologies.

Purpose of the Study:

• To propose and demonstrate a general approach for achieving angle-selective perfect light absorption in 2D materials.
• To overcome the limitations of weak light absorption in 2D materials for device applications.
• To explore novel combinations of 2D materials with photonic structures.

Main Methods:

• A general approach was proposed to achieve angle-selective perfect light absorption.
• Large-area single-layer graphene was integrated onto a structure comprising a chalcogenide layer atop a mirror.
• Experimental measurements were conducted in the mid-infrared wavelength range (~13 μm).

Main Results:

• A total absorption of 77.6% was achieved in the mid-infrared wavelength range.
• Graphene contributed a record-high 47.2% absorptivity of mid-infrared light.
• The developed structure demonstrated angle-selective perfect light absorption.

Conclusions:

• The proposed approach enables giant light absorption in 2D materials.
• The angle-selective thin optical element has significant implications for solar energy harvesting, thermal energy harvesting, photo-detection, and sensing.
• This study opens new avenues for combining 2D materials with photonic structures for novel device applications.