The topic of her studies was the development of a new technique for optical measurement of charge and voltage in GaAs type integrated circuits.

Her research areas are ultra-fast solid-state and semiconductor lasers, the development of reliable and functional instruments to generate extreme ultraviolet (EUV) X-rays and attosecond science.

She developed the first method for generating ultra-fast light pulses known as semiconductor saturable-absorber mirrors (SESAMs), which have become a worldwide industry standard for cutting and welding in fields ranging from electronics and automotive industry to communications technology, medical diagnostics and surgery and has made myriad important contributions to the field of laser science since.

[13] Dr. Keller’s earlier research into carrier envelope phase stabilization and frequency comb technology was integral to Theodor W. Hänsch and John L. Hall’s development of laser-based spectroscopy that garnered them the 2005 Nobel Prize in Physics.

Ursula Keller engages for equal rights and better career opportunities of women in fields of Science, technology, engineering, and mathematics.

She was director of a research programme of the Swiss National Science Foundation from 2010 till 2022,[27] and was the founding president of the ETH Women Professors Forum.