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Vectorial design of super-oscillatory lens
Tao Liu1, Jiubin Tan, Jian Liu
1Center of Ultra-precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin 150001, China.
Optics Express
|July 12, 2013
Summary
This study introduces a new vectorial design method for super-oscillatory lenses (SOLs) to achieve tight focusing of radially polarized vector beams. Optimized SOLs create subwavelength focal spots without significant side lobes, enabling advanced optical applications.
Area of Science:
- Optics and Photonics
- Electromagnetism
- Nanotechnology
Background:
- Super-oscillatory lenses (SOLs) are crucial for subwavelength focusing.
- Efficient vectorial design of SOLs for vector beams remains a challenge.
Purpose of the Study:
- To propose a vectorial design and optimization method for SOLs.
- To achieve tight focusing of radially polarized vector beams.
- To create subwavelength focal spots with minimal side lobes.
Main Methods:
- Vectorial angular spectrum theory for SOL design.
- Genetic algorithm for structure optimization.
- Fast Hankel transform algorithm for computational acceleration.
- Vectorial Rayleigh-Sommerfeld diffraction integral for validation.
Main Results:
- A subwavelength focal spot of approximately 0.25λ is achieved.
- The focal spot exhibits minimal side lobes.
- The method is validated against established diffraction integral methods.
- An oil-immersed SOL with a 1mm diameter demonstrates the capability.
Conclusions:
- The proposed vectorial design method enables efficient SOL design for various vector beams.
- Subwavelength focusing in a post-evanescent plane is achievable.
- This method facilitates the creation of high-performance optical focusing elements.
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