Tunable Anomalous Scattering and Negative Asymmetry Parameter in a Gain-Functionalized Low Refractive Index Sphere

Area of Science:

• Optics
• Photonics
• Materials Science

Background:

• Low refractive index passive spheres typically exhibit strong forward scattering.
• This phenomenon is attributed to weak interference between electric and magnetic scattering channels.
• The asymmetry parameter is usually positive for such spheres.

Purpose of the Study:

• To investigate the forward scattering of light by gain-functionalized low refractive index dielectric spheres.
• To explore the potential of tuning optical gain to control scattering properties.
• To achieve zero forward scattering and a negative asymmetry parameter in low refractive index spheres.

Main Methods:

• Analytical investigation of light scattering.
• Numerical simulations of scattering phenomena.
• Analysis of optical gain effects on dielectric spheres.

Main Results:

• Tuning optical gain optimizes interference between scattering channels.
• Achieved zero forward scattering and negative asymmetry parameter for low refractive index spheres.
• Demonstrated an anomalous scattering regime with scattering mean free path and extinction mean free path exceeding transport mean free path.

Conclusions:

• Gain-functionalized dielectric spheres offer a novel method to control light scattering.
• This approach enables unique optical regimes with implications for light propagation.
• Provided numerical guidelines for enhancing extinction mean free path without preferential back-scattering.