High-aspect-ratio line focus and plasma production using a random phase plate.

Area of Science:

• Optics and Photonics
• Plasma Physics
• X-ray Laser Science

Background:

• Random phase plates are utilized for beam shaping in laser systems.
• Generating a line focus is crucial for applications like laser plasma production.
• Previous methods for line focus generation have limitations.

Purpose of the Study:

• To describe the use of rectangular-element random phase plates for generating a line focus.
• To investigate design modifications for achieving a more uniform line focus.
• To characterize laser plasma produced with these plates and assess its suitability for X-ray laser applications.

Main Methods:

• Fabrication and testing of rectangular-element random phase plates.
• Comparison of experimental focal patterns with theoretical calculations using an interference code.
• Generation of laser plasma using a Raman-shifted KrF laser and phase plates.
• Characterization of plasma conditions using time-resolved extreme UV spectroscopy and a pinhole camera.

Main Results:

• Experimental line focus patterns showed good agreement with theoretical predictions.
• The interference code was used to explore design modifications for a square-topped line focus.
• Laser plasma was successfully generated and characterized.
• The characterized plasma conditions were evaluated for X-ray laser applications.

Conclusions:

• Rectangular-element random phase plates are effective for generating line foci.
• Theoretical modeling aids in optimizing phase plate designs for improved focus uniformity.
• The generated laser plasma shows potential for X-ray laser applications.