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Size-dependent two-photon absorption in circular graphene quantum dots.

Xiaobo Feng, Xin Li, Zhisong Li

|February 25, 2016

Summary

This summary is machine-generated.

We theoretically investigated size-dependent two-photon absorption (TPA) in circular graphene quantum dots (GQDs). Intraband transitions significantly contribute to TPA, and TPA peaks are tunable by GQD size.

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Area of Science:

Condensed matter physics
Quantum mechanics
Materials science

Background:

Graphene quantum dots (GQDs) exhibit unique electronic and optical properties.
Two-photon absorption (TPA) is a crucial nonlinear optical process with applications in various fields.
Understanding the size-dependence of TPA in GQDs is essential for their technological applications.

Purpose of the Study:

To theoretically investigate the size-dependence of two-photon absorption (TPA) in circular graphene quantum dots (GQDs).
To derive analytical expressions for the TPA coefficient and transition selection rules.
To analyze the contribution of intraband and interband transitions to TPA.

Main Methods:

Solving the Dirac-Weyl equation analytically under the infinite-mass boundary condition to obtain electronic energy states.
Deriving analytical expressions for the TPA coefficient considering arbitrary size-distributions.
Analyzing the transition selection rules for TPA in GQDs.

Main Results:

Intraband transitions within the conduction and valence bands contribute significantly more to TPA than interband transitions.
The energy spectrum and TPA peak positions are tunable by altering the size of the GQDs.
Analytical expressions for TPA coefficient and selection rules were successfully derived.

Conclusions:

The size of circular graphene quantum dots plays a critical role in tuning their two-photon absorption properties.
Intraband transitions are dominant contributors to TPA in GQDs, offering potential for optical applications.
Theoretical insights provide a foundation for designing GQD-based optoelectronic devices.