Coherent control of light interaction with graphene

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Graphene exhibits unique optical properties due to its 2D structure and electronic band structure.
• All-optical modulation is crucial for developing advanced optical communication and computing systems.
• Controlling light-matter interactions at the nanoscale is a key challenge in photonics.

Purpose of the Study:

• To experimentally demonstrate all-optical modulation of light using a graphene film.
• To investigate the modulation efficiency of light transmission and scattering in graphene.
• To explore the potential of graphene for sub-wavelength optical switching and modulation.

Main Methods:

• Utilizing a Sagnac interferometer with counter-propagating laser beams to create a standing wave.
• Scanning a graphene film across the standing wave to induce modulation via coherent absorption.
• Analyzing on-axis transmission and off-axis scattered optical signals to quantify modulation.

Main Results:

• Achieved nearly 80% efficiency in modulating on-axis light transmission through the graphene film.
• Observed significant modulation of scattered optical energy, minimized at nodes and maximized at antinodes of the standing wave.
• Demonstrated the ability to switch and modulate optical interactions with deeply sub-wavelength graphene films.

Conclusions:

• Graphene films can effectively perform all-optical modulation of light.
• The observed modulation of transmission and scattering highlights graphene's potential in optical control.
• This work opens possibilities for novel photonic devices utilizing graphene for sub-wavelength optical modulation.