Radiation emission in laser-wakefields driven by structured laser pulses with orbital angular momentum.

Area of Science:

• Physics
• Materials Science
• Chemistry
• Biology

Background:

• High-intensity X-ray sources are crucial for advanced scientific research.
• Laser-plasma accelerators generate X-rays via electron betatron oscillations.
• Existing betatron sources require higher photon numbers and better tunability for broader applications.

Purpose of the Study:

• To demonstrate a novel laser-wakefield betatron source configuration.
• To increase X-ray emission energy and photon energy tunability.
• To provide flexibility in tuning X-ray properties independently of plasma parameters.

Main Methods:

• Detailed 3D simulations were performed.
• A novel configuration combining two Laguerre-Gaussian pulses was employed.
• Pulses with non-zero net orbital angular momentum were used to induce wakefield rotation.

Main Results:

• The new configuration increases X-ray emission energy.
• Enhanced flexibility in tuning X-ray photon energy was achieved.
• Helical motion, driven by laser rotation, dominates radiation emission, surpassing betatron oscillations.
• Radiation can be tuned independently of plasma parameters by controlling laser spot size and orbital angular momentum.

Conclusions:

• The novel configuration offers significant improvements for laser-wakefield betatron X-ray sources.
• This advancement enables new experimental possibilities in various scientific fields.
• The independent tunability of X-ray properties represents a major breakthrough.