Large tunable optical absorption of CVD graphene under total internal reflection by strain engineering

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Graphene's optical properties are crucial for optoelectronic applications.
• Controlling light-matter interactions in graphene is an active research area.
• Strain engineering offers a promising route to tune material properties.

Purpose of the Study:

• To investigate the strain-induced tuning of polarization-dependent optical absorption in chemical vapor deposition (CVD) graphene.
• To explore the effect of total internal reflection (TIR) on strain-induced optical absorption modulation.
• To assess the potential of this method for novel optical devices and sensors.

Main Methods:

• Developed a method for strain engineering of large-scale CVD graphene.
• Utilized total internal reflection (TIR) geometry for optical absorption measurements.
• Varied strain direction to tune absorption for transverse magnetic (TM) and transverse electric (TE) waves.

Main Results:

• Demonstrated independent tuning of optical absorption for TM and TE waves by controlling strain direction.
• Observed a significant increase in strain-induced tunability of optical absorption under TIR compared to normal incidence.
• Achieved a threefold increase in modulation efficiency for monolayer graphene under TIR.

Conclusions:

• Strain engineering of graphene under TIR significantly enhances optical absorption tunability.
• This technique offers a novel pathway for developing ultra-thin optical devices.
• The high strain sensitivity of graphene under TIR is promising for advanced strain sensor applications.