Instrumentation for dual-probe scanning near-field optical microscopy

Area of Science:

• Materials Science
• Nanotechnology
• Optics

Background:

• Understanding local carrier motions is crucial for advanced semiconductor device performance.
• Existing techniques often lack the spatial resolution and control to probe nanoscale carrier dynamics effectively.

Purpose of the Study:

• To develop and demonstrate a dual-probe scanning near-field optical microscope (SNOM) for investigating local carrier motions.
• To achieve precise control over probe-sample and inter-probe distances for enhanced optical measurements.

Main Methods:

• Designed a dual-fiber probe SNOM system for simultaneous photoexcitation and light collection.
• Utilized finite-difference time-domain (FDTD) method for optimizing probe design and efficiency.
• Implemented dual-band modulation and real-time probe tip oscillation detection for precise distance control.

Main Results:

• Successfully developed a dual-probe SNOM capable of precise distance regulation.
• Demonstrated the ability to scan the collection probe around the illumination probe without tip damage.
• Observed carrier motions in an Indium Gallium Nitride (InGaN) quantum well using photoluminescence spectroscopy.

Conclusions:

• The developed dual-probe SNOM is a powerful tool for studying nanoscale carrier dynamics.
• The precise distance control mechanism allows for unprecedented investigation of local optical properties.
• This technique opens new avenues for characterizing semiconductor nanostructures and optimizing optoelectronic devices.