Few-cycle erbium fiber frequency combs and their applications in ultrafast condensed matter physics

Erbium fiber frequency combs have served as the backbone of frequency metrology for the past 20 years, but their use in ultrafast optical physics has lagged behind. I will discuss the development of high-power, few-cycle frequency combs from erbium fiber technology and highlight their novel applications. These applications include performing sensitive attosecond metrology measurements with solid-state high harmonic generation, uncovering attosecond electron motion in optical near fields, and directing ultrafast charge motion in 2D materials, now even extending into light-driven non-equilibrium materials. These few-cycle near-infrared sources open up new and exciting possibilities for understanding and controlling ultrafast processes in condensed matter systems.