Ultrafast Lasers

This lecture provides an overview of key concepts to passively modelocked solid-state and semiconductor lasers, as outlined in the recent textbook "Ultrafast Lasers" (Springer Verlag, 2021). This textbook gives a comprehensive introduction with step-by-step derivations of all relevant equations starting with the Maxwell equations and will allow interested students to follow up with the missing details from this short lecture. Key topics addressed in this lecture include SESAM modelocking to overcome Q-switching instabilities, soliton modelocking, the generation of few-cycle pulses with carrier-envelope offset stabilization, and the basic principles of noise characterization. The development of the single-cavity dual-comb lasers pave the way for numerous industrial applications in spectroscopy and time-resolved measurements. This lecture will explain the unique noise properties of these lasers and how this simplies dual-comb spectroscopy and dual-comb equivalent time sampling for any kind of pump-probe measurements. Additionally, the lecture will connect the dots between innovations in femtosecond and attosecond lasers and the landmark advances in frequency metrology that began in 1999.

About the Speaker

Ursula Keller, a tenured professor of physics at ETH Zurich since 1993, has shaped the field of ultrafast science. She led the NCCR MUST program from 2010 to 2022. Keller obtained her Diplom from ETH in 1984 and a Ph.D. from Stanford University in 1989. Between 1989 and 1993, she worked as a Member of Technical Staff at Bell Labs, initiating her independent research career. Keller co-founded Time-Bandwidth Products, which was acquired by JDSU in 2014, and K2 Photonics in 2023. She has served on Jenoptik's supervisory board since 2022. Her research focuses on advancing ultrafast science and technology through innovations in ultrafast solid-state and semiconductor lasers. She invented the semiconductor saturable absorber mirror (SESAM) for ultrashort pulse generation in solid-state lasers resolving the long-standing Q-switching problem. She pushed pulse generation into the one to two optical-cycle regime and pioneered carrier-envelope offset stabilization, full frequency comb generation and stabilization.  Her contributions include establishing ultrafast solid-state lasers for scientific and industrial applications and inventing new multiplexing methods for dual-comb applications. Keller's pioneering work in attosecond science includes the attoclock technique, full electric field control for petahertz electronics, and groundbreaking attosecond photoemission time delays using coincidence detection and angular resolution. Her awards include the Swiss Science Prize Marcel Benoist (2022), the OSA Frederic Ives Medal (2020), the SPIE Gold Medal (2020), the IEEE Edison Medal (2019), the OSA Charles H. Townes Award (2015), the EPS Senior Prize (2011), and two ERC advanced grants. Keller has supervised 95 Ph.D. students, authored 519 journal articles, and has an h-index of 120 with over 55,000 citations according to Google Scholar. She recently authored "Ultrafast Lasers," a graduate textbook published by Springer Verlag in 2022.