Felix Dothan (1924–2005) was a distinguished Israeli physicist whose work bridged the gap between fundamental plasma physics and the practical application of laser technology. As a long-time professor at the Hebrew University of Jerusalem’s Racah Institute of Physics, Dothan was a foundational figure in Israel’s scientific development, particularly in the realms of gas lasers and medical imaging.
1. Biography: From Zagreb to Jerusalem
Felix Dothan was born Felix Deutsch on September 8, 1924, in Zagreb, Yugoslavia (now Croatia). His early life was marked by the upheaval of World War II. Having survived the Holocaust, he immigrated to the newly established State of Israel in 1948. Like many immigrants of that era, he Hebraized his surname from Deutsch to Dothan.
Dothan’s academic journey was centered almost entirely at the Hebrew University of Jerusalem. He earned his Ph.D. under the supervision of Professor Ernst Alexander, a pioneer of Israeli experimental physics. Dothan’s early career coincided with the formative years of Israeli science; he served in the Science Corps (HEMED) of the Israel Defense Forces, where many of the country’s future scientific leaders applied their knowledge to national security challenges.
He rose through the academic ranks at the Hebrew University, eventually becoming a Full Professor of Applied Physics. He spent several decades at the Racah Institute of Physics, where he established himself as a leading authority on gas discharges and the physics of ionized gases.
2. Major Contributions: Lasers and Plasmas
Dothan’s research was characterized by a transition from the theoretical study of electrons in gases to the engineering of high-power laser systems.
- Gas Discharge Physics: Dothan conducted extensive research into the behavior of electrons in gas discharges. His work on "electron swarms" helped define how electrical currents move through various gas mixtures, which is fundamental to the creation of plasma.
- High-Power CO2 Lasers: In the 1960s and 70s, Dothan was at the forefront of developing Carbon Dioxide (CO2) lasers. These lasers were among the first to produce high-power continuous waves, making them essential for industrial cutting, welding, and—crucially—surgery.
- Medical Physics and Imaging: Later in his career, Dothan pivoted toward the pedagogical and theoretical aspects of medical physics. He recognized that the rapid advancement of MRI, CT, and X-ray technology required a rigorous physical framework that medical practitioners could understand.
- Industrial Applications: He was a strong advocate for "Applied Physics," ensuring that laboratory discoveries were translated into the Israeli high-tech industry. His work contributed to the development of laser-based defense systems and industrial tools.
3. Notable Publications
Dothan was a prolific writer of both technical papers and educational texts. His most influential works include:
- "Physical Principles of Medical Imaging": While several textbooks share this title, Dothan’s contributions (often published in Hebrew as Ekronot Ha-Phizika Shel Hadama Refuit) became the standard reference for Israeli students of medicine and radiology, demystifying the complex mathematics of wave mechanics and nuclear resonance.
- "Energy Gain of Electrons in a Laser Discharge" (1970s): A series of papers published in the Journal of Applied Physics and Applied Physics Letters that detailed the kinetics of gas lasers.
- "The Physics of Medical Imaging": Dothan’s research papers in the 1980s focused on the optimization of X-ray tubes and the reduction of radiation doses in diagnostic imaging.
4. Awards and Recognition
While Dothan was not a recipient of the Nobel Prize, he was held in the highest esteem within the international physics community and the Israeli state:
- Professor Emeritus: Upon his retirement, he was named Professor Emeritus at the Hebrew University, an honor reflecting a lifetime of service.
- The Ben-Gurion Award (contributor): While the award is often given to individuals, Dothan was part of the collective of "Founding Scientists" often recognized for building Israel's scientific infrastructure.
- International Fellowships: He held several visiting positions at prestigious institutions, including CERN in Geneva and various research laboratories in the United States, where he collaborated on plasma acceleration.
5. Impact and Legacy
Felix Dothan’s legacy is visible in two primary areas:
The Israeli Laser Industry
Israel is currently a global leader in medical aesthetics and surgical laser technology (companies like Lumenis and Alma Lasers). This industry owes its existence to the foundational research conducted by Dothan and his contemporaries in the 1960s and 70s. They proved that lasers could be controlled with enough precision to be used on human tissue.
Education of Physicists
Dothan was known as a "physicist’s physicist." He had a rare ability to explain the most complex phenomena—such as the quantum behavior of gas molecules—in a way that was accessible to engineers and doctors. Many of his students went on to lead departments in Israeli universities and R&D divisions in the private sector.
6. Collaborations
Dothan worked closely with Shaul Yatsiv, another giant of Israeli laser physics. Together, they turned the Hebrew University into a hub for spectroscopy and quantum electronics. He also maintained long-term research relationships with the Weizmann Institute of Science and collaborated with the Israeli Ministry of Defense on high-energy projects that remain partially classified.
7. Lesser-Known Facts
- A Family of Scholars: Felix was the brother of Moshe Dothan, one of Israel’s most famous archaeologists. While Felix looked into the future through the lens of a laser, his brother looked into the past, excavating sites like Ashdod and Hamat Tiberias. His sister-in-law, Trude Dothan, was also a world-renowned archaeologist specializing in the Philistines.
- The "Science Corps" Roots: Dothan was part of the generation that literally built laboratories out of repurposed equipment after the 1948 war. His career reflects the "can-do" spirit of early Israeli science, where theoretical physicists were expected to be able to blow their own glass tubes for vacuum experiments.
- Polymath Interests: Beyond the lab, Dothan was known for his deep interest in history and linguistics, a trait common among the European-born "Generation of Founders" in Israel.
Felix Dothan passed away in 2005, leaving behind a legacy that continues to resonate in every hospital that uses a laser scalpel and every university that teaches the intricate dance of the plasma state.