Two-dimensional quantitative near-field phase imaging using square and hexagonal interference devices.

Area of Science:

• Plasmonics and Nanophotonics
• Near-field Optics
• Surface Plasmon Polaritons

Background:

• Controlling near-field phase is crucial for advanced optical imaging.
• Surface plasmon polaritons (SPPs) offer unique light-matter interaction properties.
• Existing methods lack precise control over near-field phase distributions.

Purpose of the Study:

• To demonstrate the formation of near-field phase distributions using surface plasmon interference devices.
• To experimentally image and quantitatively analyze these phase distributions.
• To investigate the origin and control mechanisms of the near-field phase.

Main Methods:

• Fabrication of surface plasmon interference devices.
• Near-field phase microscopy for quantitative phase imaging.
• Control of illumination polarization and device area.
• Numerical and analytical electromagnetic modeling.

Main Results:

• Demonstrated formation of near-field with non-trivial phase distribution.
• Phase distribution controlled by illumination polarization and device geometry.
• Identified the out-of-plane electric component of SPPs as the origin of the near-field phase.
• Successfully formed near-field plane waves with controllable propagation directions.

Conclusions:

• Surface plasmon interference devices enable precise control over near-field phase.
• The developed models accurately predict and explain the observed phase phenomena.
• This work paves the way for near-field imaging and tomography of phase objects.