Development of a gas cell using the laser micromachining technique

Abstract

Laser micro-machining is widely used in industries and research. This technology can machine fine structures precisely compared with the ordinary mechanical machining technology. For laser micro-marching, femto-second (fs) lasers can be used as they have a short pulse and the interaction time with the materials is short, leading to less thermal effect on the target. In our research group, a fs laser micro-machining system was developed and it was used for fabrication of a special type of a gas cell that will be utilized for laser wakefield acceleration. The fs laser machining system consists of a mode-locked Ti:sapphire oscillator, a Ti:sapphire regenerative amplifier, a focusing lens, and a 3-axis moving stage controlled by a LABVIEW-based software. We used the developed laser machining system to fabricate a special-type gas cell, which will be used as a plasma source in laser wakefield acceleration. The special gas cell, which has a curved gas flow line inside, was designed by using the computational-fluid-dynamics (CFD) simulations, and the operation characteristics for the gas cell was analyzed by a Mach-Zehnder interferometry. The curved gas cell has some advantages, for example, the internal gas density profiles can be controlled for optimum laser wakefield acceleration, aiming to produce higher electron beam energies.