Gold-bead scanning near-field optical microscope with laser-force position control

Area of Science:

• Optics
• Nanotechnology
• Microscopy

Background:

• Conventional optical microscopes are limited by the diffraction limit of light.
• High-resolution imaging requires techniques that overcome diffraction limitations.

Purpose of the Study:

• To develop a scanning near-field optical microscope (SNOM) with enhanced sensitivity.
• To achieve nanoscale resolution using a sub-wavelength metallic probe particle.

Main Methods:

• Development of a SNOM utilizing an optically trapped metallic particle with a 40 nm diameter.
• Employing spot illumination to increase scattered light intensity from the probe.
• Utilizing the SNOM to scan and image the surface of cover glass.

Main Results:

• Detection of surface irregularities on cover glass at a depth of approximately 10 nm.
• Successful observation of gold colloidal particles on the cover glass surface.
• Demonstration of nanoscale imaging capabilities with the developed SNOM.

Conclusions:

• The developed SNOM with a sub-wavelength metallic probe offers high-resolution surface imaging.
• The technique is capable of detecting subtle surface features and nanoparticles.
• This method advances near-field optical microscopy for nanoscale surface analysis.