Measurement of the linewidth of a home-built vacuum ultraviolet comb by frequency comb spectroscopy on NO.

Optical frequency comb in the vacuum ultraviolet (VUV)/extreme ultraviolet (XUV) region has attracted a great deal of attention, as it provides coherent VUV/XUV radiation source with a rather narrow bandwidth, facilitating precise spectroscopic measurements in the short wavelength regime. In this study, we report on the linewidth measurement of a home-built VUV comb centered at 148 nm using direct frequency comb spectroscopy with NO. The measurement reveals that the upper bound of our comb linewidth is less than 28 MHz.