Wiggins S M, Reijnders M P, Abuazoum S, Hart K, Welsh G H, Issac R C, Jones D R, Jaroszynski D A
Scottish Universities Physics Alliance, Department of Physics, University of Strathclyde, Glasgow G4 0NG, United Kingdom.
Rev Sci Instrum. 2011 Sep;82(9):096104. doi: 10.1063/1.3640410.
Gas-filled capillary discharge waveguides are important structures in laser-plasma interaction applications, such as the laser wakefield accelerator. We present the methodology for applying femtosecond laser micromachining in the production of capillary channels (typically 200-300 μm in diameter and 30-40 mm in length), including the formalism for capillaries with a linearly tapered diameter. The latter is demonstrated to possess a smooth variation in diameter along the length of the capillary (tunable with the micromachining trajectories). This would lead to a longitudinal plasma density gradient in the waveguide that may dramatically improve the laser-plasma interaction efficiency in applications.
