Silicon substrate significantly alters dipole-dipole resolution in coherent microscope

Area of Science:

• Optics and Photonics
• Microscopy Techniques
• Materials Science

Background:

• Coherent microscopy performance is influenced by substrate properties.
• High refractive index substrates, such as silicon, offer unique optical interactions.
• Conventional modeling often assumes no substrate or standard glass substrates.

Purpose of the Study:

• To investigate the impact of high refractive index substrates on coherent microscopy imaging.
• To analytically derive the dyadic Green's function for a substrate-inclusive optical setup.
• To compare imaging performance metrics (magnification, depth of field, resolution) with different substrates.

Main Methods:

• Derivation of the analytical expression for the 3D full-wave vectorial point spread function (dyadic Green's function).
• Numerical analysis comparing silicon, glass, and no-substrate conditions.
• Evaluation of resolution, magnification, and depth of field variations.

Main Results:

• Novel insights into resolution enhancement via silicon substrate near-field effects.
• Demonstration that resolution is highly sensitive to the relative positions of sources and the substrate interface.
• Observed that both improved and degraded resolution compared to glass substrates are possible with minor positional adjustments.

Conclusions:

• A single, indicative resolution number is not feasible or advisable for silicon substrates in coherent microscopy.
• Precise positioning is critical for optimizing or predicting imaging performance with high refractive index substrates.
• Understanding near-field effects is key to leveraging silicon substrates for potential resolution improvements.