Refractive index dispersion measurement using carrier-envelope phasemeters

Abstract

We introduce a novel method for direct and accurate measurement of refractive index dispersion based on carrier-envelope phase detection of few-cycle laser pulses, exploiting the difference between phase and group velocity in a dispersive medium. In a layout similar to an interferometer, two carrier-envelope phasemeters are capable of measuring the dispersion of a transparent or reflective sample, where one phasemeter serves as the reference and the other records the influence of the sample. Here we report on proof-of-principle measurements that already reach relative uncertainties of a few 10 ^−4 . Further development is expected to allow for unprecedented precision.

Keywords

• wave propagation
• optical and dielectric properties
• ultrafast processes
• photoionization
• carrier-envelope phase
• refractive index dispersion