Direct generation of Bessel beams.

Area of Science:

• Optics and Photonics
• Nonlinear Optics
• Laser Physics

Background:

• Bessel beams are non-diffracting beams with unique propagation characteristics.
• Traditional methods for generating Bessel beams often require spatial filtering of Gaussian beams, which can be inefficient.
• Direct generation methods are sought for improved efficiency and simplified experimental setups.

Purpose of the Study:

• To identify and describe two distinct implementations for the direct generation of Bessel beams.
• To provide theoretical and numerical support for the proposed generation mechanisms.
• To explore the potential of nonlinear optical processes for Bessel beam creation.

Main Methods:

• Implementation 1: Design and analysis of a stable optical resonator supporting a Bessel beam as its lowest-loss transverse mode.
• Numerical simulations to validate geometrical optics predictions for the resonator.
• Implementation 2: Exploitation of the angular plane-wave spectrum theorem for Bessel beams and its realization via phase-matching in a four-wave mixing (FWM) process.

Main Results:

• A resonator configuration was identified where Bessel beams naturally form as stable modes.
• Numerical simulations confirmed the validity of the geometrical optics approach for the resonator.
• The FWM process in nonlinear materials was shown to generate anti-Stokes radiation that propagates as a Bessel beam.

Conclusions:

• Two viable methods for direct Bessel beam generation have been demonstrated, offering alternatives to conventional techniques.
• The resonator method provides a stable platform for Bessel beam generation.
• Nonlinear optical frequency conversion offers a novel route to generating Bessel beams, with potential applications in materials processing and imaging.