Scannable Dual-Focus Metalens with Hybrid Phase

Area of Science:

• Optics
• Nanotechnology
• Materials Science

Background:

• Dual-focus metalenses are crucial for applications like tomography and optical tweezers.
• Current dual-focus metalenses with hyperbolic phases suffer from off-axis aberrations, limiting beam scanning capabilities.
• Vibration-free, high-speed beam scanning is essential for practical applications.

Purpose of the Study:

• To develop a dual-focus metalens capable of efficient beam scanning.
• To overcome the limitations of off-axis aberrations in conventional dual-focus metalenses.
• To enable high-speed optical manipulation and imaging without mechanical vibrations.

Main Methods:

• Designed a novel metalens utilizing a "hybrid phase".
• The hybrid phase combines a hyperbolic phase (inner) and a quadratic phase (outer).
• This design aims to reduce off-axis aberrations while maintaining a high numerical aperture.

Main Results:

• Demonstrated a scannable dual-focus metalens.
• The metalens exhibits stable dual-focus performance with minimal distortion for incident angles up to 2.5°.
• The design is adaptable for multifocus metalenses, expanding its applicability.

Conclusions:

• The developed hybrid phase metalens effectively enables beam scanning.
• This advancement is significant for high-speed optical techniques requiring precise beam control.
• The scannable multifocus metalens design opens new avenues in optical imaging and manipulation.