Direct patterning of vortex generators on a fiber tip using a focused ion beam

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Optical fibers are crucial for telecommunications and sensing.
• Generating complex light beams often requires bulky external optics.
• Integrating beam-shaping capabilities directly into optical fibers is highly desirable.

Purpose of the Study:

• To demonstrate the fabrication of spiral phase optical elements directly on optical fiber ends.
• To confirm the generation of phase singularity in the output beam.
• To explore applications in all-fiber beam shaping and optical trapping.

Main Methods:

• Focused ion beam (FIB) milling using a 30 keV Ga+ ion beam.
• Direct etching of continuous spiral phase plates and fork gratings on fiber tips.
• Interference experiments to measure phase characteristics of the output beam.

Main Results:

• Successful fabrication of spiral phase optical elements on cleaved optical fiber ends.
• Experimental confirmation of phase singularity in the output beam, validating the fabricated structures.
• Demonstration of a method for creating integrated fiber-optic beam manipulation devices.

Conclusions:

• Focused ion beam milling is an effective technique for creating advanced optical elements on fiber tips.
• The fabricated spiral phase elements enable on-fiber generation of beams with phase singularity.
• These all-fiber devices hold significant promise for optical trapping and beam shaping applications.