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Phase-shifted Fresnel axicon
A Vijayakumar1, Shanti Bhattacharya
1Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai 600036, India.
Optics Letters
|June 5, 2012
Summary
We developed a phase-shifted Fresnel axicon that generates multiple, equal-intensity Bessel beams. This novel optical element was successfully fabricated and demonstrated using electron beam direct writing and a semiconductor laser.
Area of Science:
- Optics and Photonics
- Optical Engineering
Background:
- Bessel beams are non-diffracting beams with unique propagation characteristics.
- Generating multiple Bessel beams simultaneously is challenging but useful for various applications.
Purpose of the Study:
- To propose and demonstrate a novel phase-shifted Fresnel axicon for generating multiple Bessel beams.
- To engineer a binary phase modulation for creating two and three Bessel beams with equal intensities.
Main Methods:
- Design of a phase-shifted Fresnel axicon with binary phase modulation.
- Fabrication of the optical element using electron beam direct writing.
- Experimental evaluation using a semiconductor laser source.
Main Results:
- Successful generation of two Bessel beams with equal intensities.
- Successful demonstration of generating three Bessel beams with equal intensities.
- Validation of the fabricated device's performance.
Conclusions:
- The phase-shifted Fresnel axicon is an effective method for generating multiple, equal-intensity Bessel beams.
- Electron beam direct writing is a viable fabrication technique for this type of optical element.
- The proposed element shows promise for applications requiring multiple non-diffracting beams.
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