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Welcome to the community hub built to collect knowledge and have discussions related to Ursula Keller.
Early Life and Education Timeline
Birth in Zug, Switzerland
June 21, 1959
Ursula Keller was born in Zug, Switzerland, marking the beginning of her life journey. Details about her early childhood and family background in Zug are scarce but shaped her initial exposure to the world.
Physics Studies at ETH Zurich
1978-1984
Keller pursued her undergraduate and graduate studies in Physics at the prestigious ETH Zurich. This period was crucial for her, providing a solid foundation in physics and setting the stage for her future specialization in laser physics and photonics. She would have engaged with fundamental concepts and early research experiences that sparked her scientific curiosity.
Ph.D. in Physics at ETH Zurich
1984-1987
Continuing at ETH Zurich, Keller completed her Ph.D. in Physics. This involved intensive research and the development of her expertise in a specific area of physics. This period would have entailed rigorous study, experimentation, and the completion of a doctoral thesis, marking her transition to an independent researcher.
Main milestones
Birth in Zug, Switzerland
June 21, 1959
Ursula Keller was born in Zug, Switzerland. Her early life and upbringing laid the foundation for her future pursuit of scientific excellence. The Swiss emphasis on precision and innovation likely influenced her later work in laser physics.
Diploma in Physics, ETH Zurich
1984
Keller obtained her diploma (Master's equivalent) in Physics from the Swiss Federal Institute of Technology (ETH) Zurich, one of the world's leading science and technology universities. This marked the formal beginning of her career in physics, providing a strong foundation in theoretical and experimental physics.
Ph.D. in Physics, Stanford University
1987
Ursula Keller earned her Ph.D. in Physics from Stanford University, USA. Her doctoral research likely involved exploring the properties and behavior of laser systems, laying the groundwork for her future innovations in ultrafast laser technology. This international experience broadened her perspective and research network.
Research Scientist, AT&T Bell Laboratories
1989
Following her Ph.D., Keller joined AT&T Bell Laboratories (later Lucent Technologies), a renowned center for innovation in telecommunications. Here, she gained invaluable industrial research experience, contributing to cutting-edge developments in fiber optics and laser technology. This allowed her to apply her academic knowledge to real-world challenges.
Professor of Physics, ETH Zurich
1993
Keller returned to ETH Zurich as a Professor of Physics. This marked a pivotal moment in her career, providing her with the platform to lead her own research group and train the next generation of scientists. Her appointment demonstrated the recognition of her significant contributions to laser physics.
Development of Semiconductor Saturable Absorber Mirrors (SESAMs)
1996
Keller's group pioneered the development of Semiconductor Saturable Absorber Mirrors (SESAMs), a key enabling technology for passively mode-locked solid-state lasers. SESAMs revolutionized ultrafast laser technology by providing a reliable and versatile mechanism for generating ultrashort pulses. This invention established her as a leader in the field.
ERC Advanced Grant
2010
Keller received a prestigious Advanced Grant from the European Research Council (ERC). This substantial funding enabled her to pursue high-risk, high-reward research in attosecond science and advanced laser systems, further solidifying her research leadership.
SPIE Gold Medal
2015
Ursula Keller was awarded the SPIE Gold Medal, the highest honor bestowed by the International Society for Optics and Photonics (SPIE). This award recognized her pioneering contributions to ultrafast laser science and technology and their impact on various scientific and technological fields.
Arthur L. Schawlow Prize in Laser Science
2018
Keller received the Arthur L. Schawlow Prize in Laser Science from the American Physical Society (APS). This esteemed award honored her outstanding contributions to the fundamental understanding and advancement of laser science, further recognizing her impact on the field.
Continuing Research and Leadership at ETH Zurich
Present
As of today, Ursula Keller continues to lead a vibrant research group at ETH Zurich, pushing the boundaries of ultrafast laser science and attosecond physics. She remains a highly sought-after speaker and mentor, shaping the future of photonics research globally.
Scientific Contributions and Inventions
Development of SESAM Technology
Early 1990s
Keller is best known for her groundbreaking work on Semiconductor Saturable Absorber Mirrors (SESAMs). These devices revolutionized ultrafast laser technology by enabling the reliable and efficient generation of ultrashort laser pulses. This invention has had a profound impact on various fields, including telecommunications, medicine, and materials science.
Advancements in Ultrafast Laser Technology
Ongoing
Keller and her research group have continued to make advancements in ultrafast laser technology, exploring new materials, laser designs, and applications. This includes pushing the limits of pulse duration, power, and repetition rate, enabling new scientific discoveries and technological applications.
Academic and Research Career at ETH Zurich
Research at AT&T Bell Laboratories
1989-1993
Following her initial work, Keller spent several years as a Member of Technical Staff at AT&T Bell Laboratories, a renowned research institution. Here, she gained valuable experience in industrial research, potentially working on projects related to telecommunications and advanced materials, which enriched her skill set.
Professor at ETH Zurich
1993
Keller returned to ETH Zurich and was appointed as a professor. This was a pivotal moment, signaling her establishment as a leading academic and researcher. It allowed her to lead research groups, mentor students, and further develop her expertise in ultrafast laser technology.
Full Professor of Ultrafast Laser Physics at ETH Zurich
1997 - Present
Ursula Keller achieved the position of Full Professor of Ultrafast Laser Physics, solidifying her role as a leader in the field. Her work centered on pushing the boundaries of ultrafast laser technology, and mentoring future generations of scientists in the field.
Director of the Institute for Quantum Electronics
2010 - Present
Keller's leadership abilities were recognized as she became the Director of the Institute for Quantum Electronics at ETH Zurich. This placed her in charge of a significant research institution, directing research efforts and contributing to the overall direction of quantum electronics research.
Professional Affiliations and Memberships
Fellow of Optica (formerly OSA)
Ongoing
Keller is a Fellow of Optica (formerly the Optical Society of America), a recognition of her significant contributions to the field of optics and photonics. This reflects her standing in the scientific community.
Fellow of the IEEE
Ongoing
As a Fellow of the Institute of Electrical and Electronics Engineers (IEEE), Keller is recognized for her contributions to electrical engineering and related fields. This further demonstrates her impact across different scientific and engineering disciplines.
Personal Life and Relationships
Marriage and Family
Circa 1980s - Present
While specific details are not widely available, it is known that Ursula Keller is married and has children. Balancing a demanding career with family life is likely a significant aspect of her life. The support of family is crucial for most individuals with such demanding careers.
Mentorship and Collaboration
Ongoing
As a professor, Keller has mentored numerous students and researchers, contributing to the development of the next generation of scientists. Her collaborative work with colleagues from around the world highlights her role as a leader and collaborator in the scientific community.
Awards and Recognition
Arthur L. Schawlow Prize in Laser Science
2015
Keller was awarded the prestigious Arthur L. Schawlow Prize in Laser Science by the American Physical Society. This award recognizes outstanding contributions to fundamental laser science, highlighting her impact on the field.
IEEE Edison Medal
2018
She received the IEEE Edison Medal, a highly prestigious award for a career of meritorious achievement in electrical engineering. This underscored her broad impact and contributions to electrical engineering technology and applications of SESAM technology for advanced lasers.
Charles Hard Townes Award
2020
Keller won the Charles Hard Townes Award from Optica (formerly OSA), recognizing outstanding leadership, pioneering innovations, and major contributions to the field of quantum electronics.
Publications and Intellectual Output
Numerous Peer-Reviewed Publications
1980s - Present
Keller has authored or co-authored a vast number of peer-reviewed publications in leading scientific journals. These publications cover a wide range of topics within ultrafast laser physics and related fields, demonstrating her breadth of knowledge and expertise.
Patents and Intellectual Property
1990s - Present
Keller's inventions, particularly in the area of SESAM technology, have resulted in numerous patents. These patents protect her intellectual property and contribute to the commercialization of her research.
Presentations at International Conferences
Ongoing
Keller is a frequent speaker at international conferences, presenting her research findings and engaging with other scientists. These presentations allow her to share her knowledge and inspire others in the field.
SESAM Technology Timeline
Invention and Initial Development of SESAMs
Early 1990s
Ursula Keller's research team conceptualized, developed, and demonstrated the first SESAMs. This revolutionary invention provided a simple yet reliable approach to mode-locking lasers, leading to the generation of stable and ultrashort pulses.
Refinement and Optimization of SESAM Designs
Mid-1990s - Present
Following the initial development, Keller's team focused on refining SESAM designs and optimizing their performance for various laser systems. This included exploring new materials, structures, and fabrication techniques to enhance pulse generation capabilities.
Widespread Adoption of SESAMs in Laser Systems
Late 1990s - Present
SESAMs quickly gained popularity and were widely adopted in various laser systems, including solid-state lasers, fiber lasers, and semiconductor lasers. Their ability to generate stable and ultrashort pulses made them essential components for numerous scientific, industrial, and medical applications.
Applications of SESAMs in Various Fields
2000s - Present
SESAMs found applications in diverse fields, including optical communication, spectroscopy, microscopy, material processing, and medical imaging. Their compact size, robustness, and ease of use made them suitable for integration into various laser systems.
Impact on Ultrafast Laser Physics
Training and Mentoring of Researchers
Ongoing
Keller's position at ETH Zurich has allowed her to train and mentor a significant number of students and postdoctoral researchers, contributing to the growth and development of the field. Her students have gone on to make their own significant contributions, further amplifying her impact.
Influence on Research Directions
Ongoing
Through her publications, presentations, and leadership roles, Keller has shaped the direction of research in ultrafast laser physics. Her work has inspired others to explore new materials, laser designs, and applications, pushing the boundaries of the field.
Promotion of Scientific Collaboration
Ongoing
Keller has fostered collaboration among researchers from different institutions and countries, promoting the exchange of ideas and accelerating scientific progress. These collaborations have led to numerous joint publications and projects, advancing the field as a whole.
28 November, 2024
As of November 28, 2024, Ursula Keller's first SESAM review publication has been
cited by 2472 people.
21 June, 1959
Ursula Keller was born on June 21, 1959. She is a Swiss physicist known for her
work in ultrafast laser technology, particularly the invention of the
semiconductor saturable absorber mirror (SESAM).
Nothing was collected or created yet.
Ursula Keller
View on Wikipediafrom Wikipedia
Key Information
Ursula Keller (born 21 June 1959) is a Swiss physicist. She has been a tenured physics professor at ETH Zurich, Switzerland since 1993.[1] A pioneer in ultrafast science and technology,[2] she is known for inventing the semiconductor saturable absorber mirror (SESAM), enabling passive mode-locking of lasers and revolutionizing ultrafast laser applications in science and industry.[3] Keller led the Swiss NCCR MUST program in ultrafast science (2010–2022),[4] co-founded several companies, including Time-Bandwidth Products [5] (now part of Lumentum [6]) and K2 Photonics,[7] and published a graduate textbook "Ultrafast Laser Physics" with Springer Verlag.[8] She is highly cited [9] and received many prestigious awards. From 2012-2016 she was the founding president of the Women Professors Forum at ETH Zurich.[10]
Career
[edit]Ursula Keller grew up in a working-class family.[11] After graduating with a "diploma" degree in physics in 1984 from ETH Zurich, Switzerland, she continued her studies at Stanford University, where she obtained a master's degree in 1987, and then continued with a doctorate in 1989 in applied physics. The topic of her studies was the development of a new technique for optical measurement of charge and voltage in GaAs type integrated circuits.
From 1989 to 1993, she started her independent research as a member of technical staff at AT&T Bell's research centre in Holmdel, New Jersey, where she conducted research on photonic switching, ultra-fast laser technology and semiconductor spectroscopy and developed a method for manufacturing ultra-short pulse lasers.
In 1993, she was appointed as a tenured associate Professor of Physics at the Swiss Federal Institute of Technology in Zurich, becoming the school's first female Professor of Physics.[12] In October 1997, she became a full professor.
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 have 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.[14]
Ursula Keller has published more than 500 peer-reviewed journal papers [15] with total citation of more than 56000 and h-index of 123.[9] Her first SESAM review publication [16] has cited by 2472 people (as on 28. November 2024).
Ursula Keller has patented several inventions in the field of ultra-fast lasers for industrial and medical applications.[17]
She is the creator of the Attoclock,[18] one of the most accurate time measurement devices in the world, which can record time intervals up to a few attoseconds, the billionth part of a billionth of a second.[19]
From 2010 to 2022, Ursula Keller has been Director of the Swiss National Research Centre for Ultra-fast Molecular Sciences and Technologies (NCCR MUST),[20] funded by the Swiss National Science Foundation.[21]
Since 2014, she has been a member of the Research Council of the Swiss National Science Foundation.[19]
In 2018, Ursula Keller won the European Inventor Award in the "Lifetime Achievement ".[17] In 2019, she was appointed as one of the leading experts that judges proposals for this award.[22]
She won the IEEE Photonics Award[23] in 2018 and the IEEE Edison Medal[24] in 2019.
She won the 2020 Gold Medal from the Society of Photo-Optical Instrumentation Engineers[25] and the 2020 Frederic Ives Medal / Jarus Quinn Prize[26] from the Optical Society.
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.[28] In March 2019, in the context of the mobbing allegations against Marcella Carollo, Ursula Keller denounced a "lack of leadership, gender discrimination and corruption at ETH Zurich" and claimed that the reason for the proposed dismissal of her colleague was "not primarily the mobbing allegations, but her gender".[29] In the same period, Ursula Keller has been formally reprimanded by ETH Zurich, including the mention of a possible dismissal in case of recurrence.[30] Two external investigations disproved the accusations that Ursula Keller made against ETH Zurich.[31] Otherwise, the Swiss Federal Audit Office recommended more transparency in the distribution of funds.[32] The Federal Administrative Court of Switzerland ruled in 2022, that the termination was unjustified due to a lack of objectively sufficient grounds.[33]
Awards and honors
[edit]- 2003: Fellow of OSA[34]
- 1998: Zeiss Research Award, "for her pioneering work on the generation of high-power, ultra-short laser pulses using solid-state lasers".[35]
- 2004: Berthold Leibinger Innovation Prize from the Berthold Leibinger Stiftung for her Semiconductor Saturable Absorber Mirror (SESAM) invention enabling industrial mode locked solid-state lasers
- 2008: Joseph Fraunhofer Award / Robert M. Burley Prize from The Optical Society "For seminal contributions to the development and application of ultrafast lasers and notably pioneering work on semiconductor saturable absorber mode-locking."[36]
- 2013: Arthur L. Schawlow Award, Laser institute of America (LIA), LIA's highest achievement award [37]
- 2014: Fellow of the Institute of Electrical and Electronics Engineers (IEEE), 2014[38] for contributions to ultrashort pulse mode locked laser physics and technology
- 2015: Charles Hard Townes Award from The Optical Society "For seminal contributions in the fields of octave-spanning lasers, frequency comb technology, and high repetition-rate ultrafast semiconductor disc lasers."[39]
- 2017: Weizmann Women and Science Award, "In recognition of her pioneering and seminal contributions to ultrafast lasers technology and important breakthroughs in attosecond science" [40]
- 2018: European Inventor Award for laser technology in the category "Lifetime achievement."[41][17]
- 2018: IEEE Photonics Award,[23]
- 2019: IEEE Edison Medal,[24]
- 2020: SPIE Gold Medal, is the highest honor the Society bestows, "in recognition of career long pioneering contributions in ultrafast science"[42]
- 2020: Frederic Ives Medal/Quinn Prize, which recognises overall distinction in Optics, from The Optical Society "For fundamental contributions to ultrafast lasers technology, especially the development of high peak and average power oscillators and important breakthroughs in attosecond science" [43]
- 2021: Elected as an international member of the National Academy of Sciences, USA[44]
- 2022: Marcel Benoist Prize,[45] which has been dubbed the "Swiss Nobel Prize"
- 2025: Foreign Member of the Royal Society[46]
References
[edit]- ^ "Head of Research". Ultrafast Laser Physics. Retrieved 28 November 2024.
- ^ "Honors and Awards". Ultrafast Laser Physics. Retrieved 28 November 2024.
- ^ ""Swiss Nobel Prize" for Ursula Keller". ETH Zurich. 12 September 2022. Retrieved 28 November 2024.
- ^ "NCCR MUST :: NCCR MUST :: About NCCR MUST". www.nccr-must.ch. Retrieved 28 November 2024.
- ^ "Time-Bandwidth Products AG". ETH Zurich. Archived from the original on 22 February 2025. Retrieved 28 November 2024.
- ^ "Ultrafast Lasers | Lumentum Operations LLC". www.lumentum.com. Archived from the original on 27 February 2025. Retrieved 28 November 2024.
- ^ "K2 Photonics - Innovative dual-comb lasers". 9 May 2023. Retrieved 28 November 2024.
- ^ Keller, Ursula (2021). Ultrafast Lasers. Graduate Texts in Physics. Bibcode:2021ulla.book.....K. doi:10.1007/978-3-030-82532-4. ISBN 978-3-030-82531-7.
- ^ a b "Ursula Keller". scholar.google.com. Retrieved 28 November 2024.
- ^ "Women Professors Forum". Women Professors Forum. Retrieved 28 November 2024.
- ^ "Role Model: Dr. Ursula Keller – We Shape Tech". Retrieved 28 November 2024.
- ^ Logean, Sylvie (25 April 2018). "Ursula Keller a vu la lumière au bout du laser". Le Temps (in French).
- ^ "The Group". ulp.ethz.ch. Retrieved 23 October 2019.
- ^ "Ursula Keller - Engineering and Technology History Wiki". ethw.org. Retrieved 23 October 2019.
- ^ "Journal Articles". Ultrafast Laser Physics. Retrieved 28 November 2024.
- ^ "Semiconductor saturable absorber mirrors (SESAM's) for femtosecond to nanosecond pulse generation in solid-state lasers". scholar.google.com. Retrieved 28 November 2024.
- ^ a b c "Swiss physicist wins European Inventor Award for laser technology". SWI swissinfo.ch. Retrieved 8 June 2018.
- ^ "Attoclock". Ultrafast Laser Physics. Retrieved 28 November 2024.
- ^ a b Echos, Les (3 May 2018). "Des impulsions laser ultrarapides pour l'industrie et la médecine". lesechos.fr (in French). Archived from the original on 14 December 2018. Retrieved 14 December 2018.
- ^ "NCCR MUST :: NCCR MUST :: About NCCR MUST". www.nccr-must.ch. Retrieved 28 November 2024.
- ^ "NCCR MUST". Swiss National Science Foundation (SNSF) (in German). Retrieved 28 November 2024.
- ^ Office, European Patent. "European Inventor Award: jury members". www.epo.org. Retrieved 21 January 2019.
- ^ a b "IEEE Photonics Award Recipients". IEEE. Archived from the original on 5 May 2018. Retrieved 10 May 2020.
- ^ a b "IEEE Edison Medal Recipients". IEEE. Archived from the original on 5 September 2018. Retrieved 10 May 2020.
- ^ "Gold Medal Winner Ursula Keller Among SPIE Award Honorees". www.photonics.com. Retrieved 10 May 2020.
- ^ "OSA Honors Ursula Keller with Highest Award". www.photonics.com. Retrieved 10 May 2020.
- ^ "NCCR MUST :: NCCR MUST :: About NCCR MUST". www.nccr-must.ch. Retrieved 26 November 2024.
- ^ "Prof. Dr. Ursula Keller | Women In Science". www.weizmann.ac.il. 25 April 2017. Archived from the original on 12 October 2018. Retrieved 14 December 2018.
- ^ Aeschlimann, Silvan; Bühler, Dennis; Osswald, Dominik (22 March 2019). "Interview of Ursula Keller with the Online Platform "Republik"". Republik. Retrieved 10 May 2020.
- ^ "NZZ am Sonntag, May 11, 2019". Retrieved 10 May 2020.
- ^ "Tagesanzeiger, July 11, 2019". Retrieved 10 May 2020.
- ^ "Die Tragik der ersten Physik-Professorin". Limmattaler Zeitung. 23 July 2022. Retrieved 5 August 2022.
- ^ "Judgment of the Federal Administrative Court" (PDF). Federal Administrative Court. 6 April 2022. Retrieved 25 November 2024.
- ^ "Ursula Keller | Optica". www.optica.org. Retrieved 3 July 2024.
- ^ "ZEISS Research Award". www.zeiss.com. Retrieved 28 November 2024.
- ^ "Joseph Fraunhofer Award / Robert M. Burley Prize". The Optical Society.
- ^ "Arthur L. Schawlow Award", Wikipedia (in German), 28 November 2024, retrieved 28 November 2024
- ^ "2014 elevated fellow". IEEE Fellows Directory. Archived from the original on 13 December 2013.
- ^ "Charles Townes Award". The Optical Society.
- ^ "Ursula Keller receives Weizmann Women & Science Award". www.phys.ethz.ch. 7 June 2017. Retrieved 14 December 2018.
- ^ Six award winning inventors changing the world. Euronews, 7 June 2018. Retrieved 7 June 2018.
- ^ "Ursula Keller: The 2020 SPIE Gold Medal". SPIE. 13 November 2019. Retrieved 26 November 2019.
- ^ "Frederic Ives Medal / Jarus W. Quinn Prize". The Optical Society. Retrieved 10 May 2020.
- ^ "2021 NAS Election". www.nasonline.org. Retrieved 17 May 2021.
- ^ "Past laureates – Marcel Benoist Foundation". marcel-benoist.ch. Retrieved 28 November 2024.
- ^ "Exceptional scientists elected as Fellows of the Royal Society". Royal Society. 20 May 2025. Retrieved 22 May 2025.
External links
[edit]
Ursula Keller
View on Grokipediafrom Grokipedia
Early life and education
Background and family
Ursula Keller was born on 21 June 1959 in Zug, Switzerland. [4] She grew up in a working-class family in Cham, a town in the canton of Zug in central Switzerland. [8] Keller has described her origins as coming from a working-class background in a semi-rural part of Switzerland, where she was the first in her family to attend university. [9] Her parents worked hard to provide better opportunities for their children. [8] She has framed her later achievements as a success story enabled by Switzerland's accessible and high-quality education system despite these socioeconomic starting points. [9] This background, including traditional expectations that women primarily become housewives in an era when Swiss women gained full voting rights only in 1971, contributed to her determination and has informed her subsequent advocacy for underrepresented groups in STEM. [9]Education and doctoral work
Ursula Keller received her Diplom degree in physics from ETH Zurich in 1984, graduating with top-ranked results. [10] [2] [1] She then moved to the United States for graduate studies at Stanford University, supported by a Fulbright fellowship. [3] At Stanford, she earned a Master of Science degree in applied physics in 1987, followed by a Ph.D. in applied physics in 1989. [7] [10] [1] After completing her doctorate, she began her professional research career as a Member of Technical Staff at AT&T Bell Laboratories. [10] [3]Career
Work at AT&T Bell Laboratories
Ursula Keller served as a Member of Technical Staff at AT&T Bell Laboratories in Holmdel, New Jersey, from 1989 to 1993, where she began her independent research career. [11] [12] During this period, she conducted research on photonic switching, ultrafast laser technology, and semiconductor spectroscopy. [11] [12] She developed methods for manufacturing ultra-short pulse lasers as part of her work in ultrafast laser systems. [13] This industrial research experience provided the foundation for her subsequent academic career, leading to her appointment at ETH Zurich in 1993. [12]Professorship at ETH Zurich
Ursula Keller was appointed tenured Associate Professor of Physics at ETH Zurich in March 1993, becoming the first woman to hold a tenured professorship in physics at the institution. [3] [14] This appointment came at the age of 33 and represented a pioneering step for gender diversity in the field at ETH Zurich. [4] She held the associate professorship until her promotion to Full Professor of Quantum Electronics in 1997, within the Institute of Quantum Electronics at the Department of Physics. [4] [5] In her role as professor, Keller directed research efforts centered on ultrafast solid-state and semiconductor lasers, the generation of extreme ultraviolet (EUV) and soft X-rays, and attosecond science, establishing these as core areas of her group's work at ETH Zurich. [15] During this period, foundational technologies for her later contributions were developed. [7]Research contributions
Invention of SESAM technology
Ursula Keller invented the semiconductor saturable absorber mirror (SESAM) in 1992, a device that enables reliable passive mode-locking of solid-state lasers by incorporating a semiconductor saturable absorber as one of the cavity mirrors. [16] [17] [7] The SESAM absorbs low-intensity light, leading to higher losses, while providing high reflectivity for high-intensity pulses once saturation is reached, facilitating self-starting mode-locking and the generation of stable femtosecond pulses without the complexity of active modulation techniques. [16] [7] In 1992, Keller demonstrated the first passively mode-locked diode-pumped solid-state laser using SESAM technology, addressing a 25-year challenge in ultrafast laser physics and enabling orders-of-magnitude improvements in pulse duration, energy, and repetition rate. [17] This invention built on Keller's earlier ultrafast laser research at AT&T Bell Laboratories and transformed ultrafast lasers from specialized, alignment-sensitive instruments into robust, practical tools. [18] SESAM mode-locking has become the industrial standard for commercial ultrafast laser systems, widely adopted in applications across electronics, automotive, communications, and medical fields, including precision micromachining, optical communications, and surgical procedures such as eye and cancer treatments that rely on cold ablation to minimize thermal damage. [17] [16] [7] The SESAM technology has resulted in multiple patents related to ultrafast lasers, supporting its commercialization and widespread implementation in industrial settings. [7]Attosecond science and ultrafast lasers
Ursula Keller has made foundational contributions to attosecond science through the development of the Attoclock, a novel measurement technique that achieves attosecond time resolution using femtosecond laser pulses. [17] The Attoclock enables precise investigation of fundamental quantum processes, such as electron tunneling dynamics in strong laser fields, by mapping angular streaking of ionized electrons to sub-cycle time scales. [19] Her group first demonstrated the method in 2008, measuring tunneling delay times in helium and argon atoms and revealing unexpectedly small or vanishing delays that challenged existing theoretical models. [17] Further Attoclock studies probed the natural coordinates of laser-induced tunneling current flow, identifying Stark shifts and multi-electron effects in atomic systems. [20] Keller pioneered techniques for carrier-envelope phase stabilization in mode-locked lasers, with key publications appearing as early as 1999. [17] These advances facilitated reliable frequency comb generation from ultrashort pulse lasers and contributed to the development of techniques recognized by the 2005 Nobel Prize in Physics awarded to Theodor W. Hänsch and John L. Hall. Her research has also driven progress in high-harmonic generation, producing isolated attosecond pulses and attosecond pulse trains that generate coherent extreme ultraviolet and soft X-ray radiation for probing ultrafast electronic dynamics in atoms, molecules, and solids. [17] These developments in attosecond science and ultrafast lasers build upon Keller's earlier SESAM technology, which provided stable ultrashort pulse sources essential for many subsequent experiments. [17] Her prolific output includes over 500 peer-reviewed publications, an h-index of 123, and more than 56,000 citations (as of approximately 2023). [21]Leadership and institutional roles
NCCR MUST and Swiss research leadership
Ursula Keller has held prominent leadership positions in Swiss national research programs and funding bodies, particularly in advancing ultrafast science and technology. She served as director of the National Centre of Competence in Research (NCCR) MUST (Molecular Ultrafast Science and Technology) from 2010 to 2022. [22] [23] This Swiss National Science Foundation-funded initiative, co-directed with Thomas Feurer from the University of Bern, brought together researchers from ETH Zurich, the University of Bern, and other institutions to investigate ultrafast molecular and solid-state phenomena using cutting-edge laser techniques. [23] Her direction of the program built upon her pioneering contributions to ultrafast laser physics, facilitating interdisciplinary collaborations and significant scientific progress in the field. [24] From 2014 to 2018, Keller was a member of the Research Council of the Swiss National Science Foundation in the Mathematics, Natural and Engineering Sciences division. [25] In this role, she contributed to the evaluation of funding proposals and the strategic oversight of basic research support across Switzerland.Gender equality initiatives
Ursula Keller has been a leading figure in advancing gender equality at ETH Zurich, motivated by her position as the first female professor in the Department of Physics. She served as the founding president of the ETH Zurich Women Professors Forum from 2012 to 2016, an organization dedicated to supporting female professors, fostering networking, and advocating for structural improvements to increase women's representation and career advancement in academia. In 2019, Keller publicly criticized ETH Zurich for persistent gender discrimination and insufficient progress in achieving gender parity, including through open letters and media statements highlighting systemic barriers faced by women in STEM at the institution. This advocacy led to a formal reprimand from ETH leadership, who claimed her public comments damaged the university's reputation. Two external investigations disproved her accusations against ETH Zurich. [26] In 2022, the Swiss Federal Administrative Court ruled that disciplinary action related to her criticism was unjustified due to lack of objectively sufficient grounds, affirming aspects of her right to express concerns about gender equality practices. [27]Awards and honors
Ursula Keller has received numerous prestigious awards and honors for her contributions to ultrafast laser physics and attosecond science.- 2018: European Inventor Award, Lifetime Achievement category (for the invention of the semiconductor saturable absorber mirror, SESAM) [7]
- 2019: IEEE Edison Medal [1]
- 2020: OPTICA Ives Medal [1]
- 2020: SPIE Gold Medal [1]
- 2021: Elected International Member, National Academy of Sciences (USA) [2]
- 2022: Swiss Science Prize Marcel Benoist [4]
- 2025: Elected Fellow, Royal Society [1]