Microsphere oblique illumination for enhanced optical nano-imaging.

Area of Science:

• Optical microscopy
• Nanotechnology
• Image processing

Background:

• Microsphere nano-imaging offers label-free, real-time imaging with sub-diffraction resolution.
• Limitations include shallow depth of field and low contrast due to microsphere size and curvature.
• Performance is sensitive to microsphere geometry and illumination conditions.

Purpose of the Study:

• To improve the imaging contrast and resolution of microsphere nano-imaging.
• To enhance the depth of field in microsphere-based optical imaging.
• To develop an effective light manipulation strategy for microsphere imaging.

Main Methods:

• Incorporation of a specially designed filter into the microscope.
• Adjustment of illumination angle and area on the microsphere using the filter.
• Experimental validation of the filter's impact on imaging performance.

Main Results:

• Imaging contrast increased by 2.77 times.
• Resolution improved from 125 nm to 100 nm.
• Depth of field extended from 519 nm to 900 nm with a 20× objective lens.

Conclusions:

• The developed filter effectively manipulates light to establish optimal illumination conditions.
• This strategy significantly enhances imaging contrast, resolution, and depth of field in microsphere nano-imaging.
• The light manipulation approach is applicable to other optical applications utilizing microspheres.