Spatial characterization of Bessel-like beams for strong-field physics

Area of Science:

• Optics and Photonics
• Laser Physics

Background:

• Bessel-like beams are valuable for applications requiring non-diffracting light propagation.
• Existing methods for controlling Bessel-like beam properties often involve trade-offs between focal spot size and working distance.
• High-power, femtosecond laser systems demand robust optical tools for precise beam manipulation.

Purpose of the Study:

• To present a compact and tunable optical design for generating and controlling Bessel-like beams.
• To enable the use of Bessel-like beams with high-power, femtosecond laser systems.
• To overcome the limitations of current setups regarding the balance between focal spot size and effective focal length.

Main Methods:

• Utilizing a shallow angle axicon in combination with a spherical lens.
• Characterizing the focal profiles of the generated Bessel-like beams using high dynamic range imaging.
• Introducing a quantitative metric (R0.8) to define the spot size containing 80% of the beam energy.

Main Results:

• Demonstrated the ability to tune both the spot size and effective focal length of Bessel-like beams.
• Achieved comparable focal spot sizes to sharp axicons while maintaining a long effective focal length.
• Overcame the conventional compromise between long working distances and small focal spot sizes.

Conclusions:

• The proposed compact design offers a versatile tool for precise control of Bessel-like beams.
• This setup is particularly advantageous for applications in strong-field physics requiring vacuum operation.
• The ability to achieve small focal spots with long working distances enhances experimental flexibility and performance.