Rapid large-area multiphoton microscopy for characterization of graphene

Area of Science:

• Materials Science
• Optics
• Nanotechnology

Background:

• Graphene characterization is crucial for its applications.
• Conventional methods like Raman mapping can be time-consuming.
• Developing faster, high-resolution imaging techniques is essential.

Purpose of the Study:

• To investigate the use of simultaneous third-harmonic generation (THG) and multiphoton-absorption-excited fluorescence (MAEF) microscopy for graphene characterization.
• To evaluate the effectiveness of a compact 1.55 μm fiber laser source for this application.
• To compare the speed and contrast of this method with traditional Raman mapping.

Main Methods:

• Utilized simultaneous THG and MAEF microscopy.
• Employed a compact 1.55 μm mode-locked fiber laser.
• Applied the technique to single- and few-layer graphene samples on a substrate.

Main Results:

• Achieved high-contrast THG and MAEF signals from graphene, distinguishing it from the substrate.
• Demonstrated high contrast between single- and bilayer graphene.
• Observed efficient detection of structural features in few-layer graphene.

Conclusions:

• Simultaneous THG and MAEF microscopy provides a fast and accurate method for graphene characterization.
• This technique is a promising alternative to Raman mapping for both research and large-scale fabrication.
• The use of 1.55 μm excitation is significant for telecommunications and signal processing applications.