Microsphere-lens coupler with 100  nm lateral resolution accuracy in visible light

Area of Science:

• Optics and Photonics
• Nanotechnology
• Materials Science

Background:

• Traditional optical microscopy is limited by diffraction, restricting resolution.
• Superresolution techniques aim to overcome these limitations for nanoscale imaging.
• Photonic nanojets generated by microspheres offer potential for enhanced focusing.

Purpose of the Study:

• To propose and validate a microsphere-lens coupler for achieving high-resolution microimaging.
• To analyze the optical properties of photonic nanojets for optimal focusing.
• To demonstrate superresolution microimaging using a microsphere lens with a conventional optical microscope.

Main Methods:

• Theoretical analysis using the finite-difference time-domain (FDTD) method to study photonic nanojets.
• Optimization of focusing parameters including refractive index and microsphere size.
• Experimental implementation using a "non-brush scrubbing" cleaning technique and a deagglomeration method for homogeneous liquid preparation.
• Tiling a 5 µm-diameter microsphere lens onto a specimen.

Main Results:

• Achieved approximately 100 nm lateral resolution accuracy.
• Demonstrated the ability to constrain beams with near-field details.
• Validated the effectiveness of the microsphere-lens coupler in enhancing microscope resolution.
• Successfully performed superresolution microimaging using a traditional optical microscope.

Conclusions:

• The proposed microsphere-lens coupler enables superresolution microimaging with nanoscale accuracy.
• Photonic nanojet properties can be optimized through parameter adjustment for enhanced focusing.
• This technique provides a foundation for advancing superresolution microimaging capabilities.