Experimental optimization of phase-matched high-order-harmonic generation

Summary form only given. High-order-harmonic generation (HHG) has being widely studied because it is a promising method for a coherent XUV source with high peak power, short temporal width, and high brightness from a compact laser system. Such XUV sources will be used in many areas of physics and chemistry. In this study, we show the clear evidence of macroscopic phase-matching by changing a interaction length as well as an atomic density.