Coaxial probes for scanning near-field microscopy

Area of Science:

• Nanotechnology
• Microscopy
• Optical Engineering

Background:

• Scanning probe microscopy (SPM) offers high-resolution surface analysis.
• Integrating optical capabilities with SPM, like scanning near-field infrared microscopy (SNIM), enhances material characterization.
• Conventional aperture probes face limitations in combined imaging modalities.

Purpose of the Study:

• To develop and characterize coaxial aperture tips for integrated scanning near-field infrared microscopy (SNIM) and scanning force microscopy (SFM).
• To investigate the fabrication process for batch production of these novel tips.
• To analyze the optical transmission properties and the impact of design parameters on coaxial probe performance.

Main Methods:

• Development of a fabrication process for batch production of hollow metal aperture tips on silicon cantilevers.
• Utilizing focused ion beam (FIB) deposition to create the coaxial tip arrangement by inserting a metal rod into the hollow tip.
• Performing theoretical calculations using a finite integration code to model and compare transmission characteristics of coaxial versus conventional aperture probes.
• Investigating the influence of geometrical design parameters on the optical behavior of the coaxial probe.

Main Results:

• Successful fabrication of batch-produced hollow metal aperture tips integrated onto silicon cantilevers.
• Demonstration of a coaxial tip arrangement achieved through focused ion beam (FIB) metal rod deposition.
• Theoretical analysis revealing the transmission characteristics of coaxial tips compared to conventional aperture probes.
• Identification of key geometrical design parameters influencing the optical performance of the coaxial probe.

Conclusions:

• Coaxial aperture tips represent a significant advancement for combined SNIM and SFM.
• The developed fabrication process enables efficient batch production of these integrated tips.
• Understanding the influence of geometrical parameters is crucial for optimizing the optical performance of coaxial probes for advanced microscopy applications.