Reflection aspherical microlenses for planar optics fabricated by electron-beam lithography

Area of Science:

• Optics and Photonics
• Nanotechnology
• Materials Science

Background:

• Traditional microlenses often suffer from chromatic aberration, limiting their use with broadband light.
• Planar optics require compact, efficient, and versatile optical components.

Purpose of the Study:

• To propose and demonstrate reflection aspherical microlenses for aberration-free, broadband light manipulation.
• To investigate the fabrication and performance of these novel microlenses.

Main Methods:

• Fabrication of microlenses using electron-beam lithography and silver (Ag) deposition.
• Characterization of surface smoothness and optical performance, including focal length and spot size.
• Testing with incoherent white-light illumination using an array of microlenses.

Main Results:

• Successfully fabricated reflection aspherical microlenses with a smooth, designed surface.
• Demonstrated constant focal length independent of wavelength, confirming no chromatic aberration.
• Achieved diffraction-limited spot sizes at multiple wavelengths.
• Obtained multiple high-contrast images using an array of microlenses under white-light illumination.

Conclusions:

• Reflection aspherical microlenses are a viable technology for broadband, aberration-free planar optics.
• The demonstrated fabrication method yields high-quality microlenses with excellent optical performance.
• These microlenses show potential for applications requiring high-contrast imaging with white light.