Electron density characterization by use of a broadband x-ray-compatible wave-front sensor

Area of Science:

• Plasma Physics
• Wavefront Sensing
• X-ray Diagnostics

Background:

• Accurate measurement of electron density gradients is crucial for understanding laser-produced and z-pinch plasmas.
• Existing diagnostics like interferometry and moiré deflectometry have limitations in complexity and applicability.
• Soft-x-ray lasers and multikilovolt x-ray energies are relevant sources for plasma diagnostics.

Purpose of the Study:

• To examine the utility of a Hartmann wave-front sensor for measuring line-integrated electron density gradients.
• To compare the Hartmann sensor with existing diagnostic methods.
• To demonstrate the experimental feasibility of the Hartmann sensor for plasma diagnostics.

Main Methods:

• Utilized a Shack-Hartmann wave-front sensor.
• Employed a liquid-crystal spatial light modulator to simulate plasma-induced phase shifts.
• Experimentally demonstrated the technique in the visible light spectrum.

Main Results:

• The Hartmann wave-front sensor provides accurate measurements of electron density gradients.
• The sensor offers significant ease of use compared to interferometry and moiré deflectometry.
• Demonstrated capability for broadband or low-coherence-length light and high x-ray efficiency.

Conclusions:

• Hartmann wave-front sensors are a promising diagnostic tool for plasma experiments.
• The sensor's advantages include wide dynamic range, 2D gradient determination, and experimental simplicity.
• Potential applications extend to EUV lithography testing and X-ray phase imaging.