Analytical model for coherent perfect absorption in one-dimensional photonic structures.

Area of Science:

• Photonics and optical materials science
• Quantum optics and condensed matter physics

Background:

• Coherent perfect absorption (CPA) describes a phenomenon where a linear system with low intrinsic loss absorbs two incident beams simultaneously but not individually.
• Understanding CPA is crucial for developing advanced optical devices and manipulating light-matter interactions.

Purpose of the Study:

• To develop an analytical model for CPA in one-dimensional photonic structures.
• To elucidate the underlying physics, specifically the absorption-mediated interference effect.
• To identify optimal parameters for achieving broadband CPA.

Main Methods:

• Development of an analytical model for CPA in one-dimensional photonic systems.
• Investigation of an absorption-mediated interference effect, enabled by non-Hermitian physics.
• Analysis of a planar cavity model to determine optimal mirror reflectivity.
• Design of a silicon resonator for demonstrating broadband CPA.

Main Results:

• The analytical model successfully captures the physics of CPA, highlighting the role of absorption-mediated interference.
• Optimal mirror reflectivity was identified for achieving CPA in resonant cavities.
• A resonator design demonstrated CPA in a 1-μm silicon layer over a 200-nm bandwidth in the near-infrared spectrum.

Conclusions:

• The study provides a theoretical framework and practical design for achieving broadband coherent perfect absorption.
• The findings pave the way for novel applications in optical sensing, energy harvesting, and optical switching.