Mie scattering of partially coherent light: controlling absorption with spatial coherence

Area of Science:

• Optical physics
• Condensed matter physics
• Nanotechnology

Background:

• Understanding light-matter interactions is crucial for developing advanced optical devices.
• Partially coherent light sources are increasingly relevant in various applications, including nanophotonics.

Purpose of the Study:

• To theoretically investigate the absorbed power of a dielectric sphere illuminated by partially coherent light from two pinholes.
• To establish a general theory for Mie scattering of partially coherent light using the angular spectrum method.

Main Methods:

• Development of a general theory for Mie scattering of partially coherent light.
• Analytical solution of the scattering problem for a dielectric sphere illuminated by two-pinhole partially coherent light.
• Application of the angular spectrum method.

Main Results:

• Absorbed power depends intricately on the degree of coherence for spheres smaller than the skin depth.
• Coherent illumination can result in lower or higher absorbed power than incoherent light, depending on geometry.
• Specific configurations show absorbed power independent of coherence, despite internal field variations.

Conclusions:

• The absorbed power by dielectric spheres can be controlled by tuning the coherence length of incident light.
• Whispering gallery modes allow for wide-ranging control over absorbed power.
• Findings have potential applications in understanding light absorption in photovoltaic nano-devices.