Generation of extremely high-angle Bessel beams.

Area of Science:

• Optics and Photonics
• Laser Physics

Background:

• Bessel beams are non-diffracting light beams with unique propagation characteristics.
• Generating tightly focused Bessel beams typically requires complex optical setups like axicons.

Purpose of the Study:

• To present a simple and compact optical setup for generating tightly focused Bessel beams.
• To analyze the impact of optical element misalignment on Bessel beam quality.

Main Methods:

• Utilizing a half-ball lens coupled with a relay lens to form the Bessel beam.
• Experimental generation and characterization of the Bessel beam at 980 nm.
• Numerical simulations to study the effects of tilt and shift misalignment.

Main Results:

• Successfully generated a Bessel beam with a 42° cone angle, 500 µm beam length, and 550 nm core radius.
• Identified acceptable ranges of tilt and shift for maintaining beam regularity.
• Demonstrated a compact and simplified alternative to conventional axicon-based systems.

Conclusions:

• The proposed half-ball lens and relay lens system offers a practical and efficient method for Bessel beam generation.
• The study provides valuable insights into the tolerance of optical misalignments for robust Bessel beam production.