Implementation of a short-tip tapping-mode tuning fork near-field scanning optical microscope

Area of Science:

• Optics
• Materials Science
• Nanotechnology

Background:

• Near-field scanning optical microscopy (NSOM) is crucial for high-resolution optical imaging.
• Tuning fork-based NSOM systems commonly use optical fibers as probes.
• Stability and signal quality are key challenges, particularly with extended fiber probes.

Purpose of the Study:

• To implement and evaluate a novel short-tip tapping-mode tuning fork for NSOM.
• To compare the performance of the new scheme against conventional methods.
• To assess the utility of the developed system for studying nanoscale optical properties.

Main Methods:

• Implementation of a short-tip tapping-mode tuning fork probe.
• Characterization of piezoelectric signal amplitudes at various tapping frequencies.
• Comparison with bare tuning forks and standard fiber-coupled tuning forks.
• Application of the system in both collection and excitation modes.

Main Results:

• The short-tip tuning fork scheme demonstrated stable operation and a high Q factor.
• Performance was validated at the tuning fork's tapping frequency.
• The system proved advantageous for experiments requiring long optical fiber probes.

Conclusions:

• The developed short-tip tapping-mode tuning fork is a robust and effective probe for NSOM.
• This advancement facilitates experiments using longer optical fibers, enhancing experimental flexibility.
• The system successfully characterized near-field optical properties of a telecommunication optical fiber and an InGaN/GaN LED.