Cloaking apertureless near-field scanning optical microscopy tips

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Near-field scanning optical microscopy (NSOM) relies on apertureless metallic tip probes for high-resolution imaging.
• Unwanted light scattering from the entire probe, beyond the tip apex, degrades NSOM signal-to-noise ratio and resolution.
• Plasmonic behavior of metallic tips is crucial for NSOM operation but can also cause detrimental scattering.

Purpose of the Study:

• To numerically demonstrate the enhancement of NSOM performance using specifically designed plasmonic covers.
• To investigate the reduction of undesired light scattering from NSOM probes.
• To improve the signal-to-noise ratio and image resolution in NSOM systems.

Main Methods:

• Numerical simulations were performed to analyze the effect of plasmonic covers on NSOM probes.
• A covering material with near-zero real permittivity was designed to minimize scattering.
• The proposed approach was simulated using a realistic mid-infrared frequency setup with silicon carbide covers.

Main Results:

• Plasmonic covers effectively reduce undesired light scattering from the NSOM probe body, excluding the tip.
• The designed covers dramatically decrease scattering due to the tip's plasmonic behavior.
• Simulations confirmed a significant improvement in the signal-to-noise ratio and potential for enhanced image resolution.

Conclusions:

• Properly designed plasmonic covers offer a viable strategy for enhancing NSOM performance.
• This method effectively mitigates scattering issues associated with metallic tip probes in NSOM.
• The approach holds promise for advancing high-resolution optical microscopy techniques.