Theodor Wolfgang Hänsch shares one of the two 2005 physics prizes with John Hall of the USA for their independent development of laser-based precision spectroscopy. Hall and Hänsch have made it possible to measure light frequencies with an accuracy of fifteen digits, allowing lasers to be fine-tuned to produce extremely narrow-band radiation.

Theodor Hänsch joins the laboratory of Professor Arthur L. Schawlow at Stanford University, as a NATO postdoctoral fellow.

Hänsch remains at Stanford, rising to professor in 1975. He focuses on the quest for ever higher resolution and measurement precision in spectroscopy. Schawlow and Hänsch also come up with the idea of laser cooling of atomic gases.

Theodor Hänsch is invited by Professor Herbert Walther, from the University of Munich, to spend a sabbatical in Germany with an Alexander von Humboldt Senior US Scientist Award. Herbert has been, since 1976, directing a group for Laser Science in Garching, which in 1981 becomes the Max-Planck Institute of Quantum Optics.

Theodor Hänsch visits Ali Javan at the MIT and Bill Bennett at Yale University. On his way to Stanford, he also stops at the Bell Laboratories at Holmdel, where he meets Charles Shank and Herwig Kogelnik, who shows Hänsch a small pursed dye laser, pumped by a nitrogen laser made by AVCO. Once in Stanford, Hänsch proposes to make a nitrogen laser pumped dye laser so highly monochromatic that it could be used for Doppler-free saturation spectroscopy of gaseous absorption lines, which is ready by July of the same year.

Theodor Hänsch enrolls the University of Heidelberg to study physics, though his focus is mainly on mathematics for the first two years.

For his PhD thesis, Hänsch continues working on laser phenomena, especially the “Lamb Dip”. After gaining his PhD in 1969, he continues working in Heidelberg as an assistant of Professor Schmelzer.

Theodor Wolfgang Hänsch shares one of the two 2005 physics prizes with John Hall of the USA for their independent development of laser-based precision spectroscopy. Hall and Hänsch have made it possible to measure light frequencies with an accuracy of fifteen digits, allowing lasers to be fine-tuned to produce extremely narrow-band radiation.

Theodor Hänsch pursues his study of laser saturation phenomena for his PhD thesis. After obtaining his degree, the outcome of the work is published in 1970, in collaboration with Peter Toschek.

He returns to Germany in 1986 and joins the University of Munich as a professor and sets up a new laser spectroscopy lab at the Max-Planck-Institute for Quantum Optics, where he is now a director. There he develops the ‘frequency comb synthesizer’, which produces frequency measurements for light so precise that it is possible to search for changes in the fundamental physical constants of the universe over time, and also to develop accurate clocks and improved GPS technology.

Theodor Hänsch switches fields and joins Peter Toschek’s laser group at the Institute of Applied Physics at Albert-Überle-Strasse, where Professor Christoph Schmerlzer has started to design a linear accelerator for heavy ions. With Toschek’s supervision, Hänsch completes his diploma research on gas lasers.

Theodor Hänsch works at the University of Heidelberg as an assistant of Professor Schmelzer.

Theodor Hänsch joins the Betratron laboratory of Professor Hans Kopfermann, after his Vordiplom. He writes his assignment for the Grosspraktikum in the construction of a transistorized fast linear gate for a semiconductor detector of alpha particles, which is only completed after Pfor. Kopfermann dies. In 1964, Hänsch attends a meeting of the German Physical Society, which discourages him from the study of nuclear and particle physics. Instead, he becomes interested in lasers.

Theodor Hänsch accepts to join the Ludwig-Maximilians University of Munich as a Professor of Experimental Physics, and to build a new Division of Laser Spectroscopy at the Max-Planck Institute in Garching.

Theodor Hänsch goes to the University of Florence as Visiting Professor, where he participates in the creation of the European Laboratory for the Nonlinear Spectroscopy, and teaches a course on laser spectroscopy to graduate students.

Theodor Hänsch is born in Heidelberg, the son of Karl and Marta Hänsch, both originally from Poland. Karl is a businessman in the field of farming machinery. The couple has another son and one daughter. It is thanks to Karl that Theodor gains his first interest in science, as his father, disillusioned with the Nazi regime, volunteers at a pharmacy.

Theodor Hänsch enters the Helmholtz Gymnasium in Heidelberg, a school with a strong emphasis in modern languages. His father, however, enrolls him in a small class taught in Latin. It is here that Theodor Hänsch’s interest in science flourishes, both thanks to the school chemistry and physics teachers, and to the activities enjoyed outside of school, comprising reading popular science and science fiction books, as well as university textbooks from the local library.

Hänsch grows up during and after the second world war. He is educated at the Helmholtz Gymnasium. The family lives in a house that had belonged to chemist Robert Bunsen, and Theodor’s father once brings home a Bunsen burner to demonstrate some chemistry, burning table salt and explaining the sodium caused a bright yellow flame. Early on, his interest in science dominates his activities outside school.  At 16, Hänsch builds a Geiger counter and sets his sights on becoming a nuclear physicist.

Theodor Hänsch’s collaboration with A. Schawlow results in both being named “California Scientists of the Year” but the Museum of Science and Industry in Los Angeles. This event made it easier for Hänsch to be offered a tenure position as Associate Professor in Stanford, which he accepts.

Theodor Hänsch and his research group ad the Max-Planck institute, develop a new method to measure the frequency of laser light, through a decide called the optical frequency comb generator. This device is then used to measure the Lyman line of atomic hydrogen to a precision of 1 part in a hundred trillion, which makes possible to search for changes in the fundamental physical constants of the universe over time.

Theodor Wolfgang Hänsch is born in Heidelberg, Germany, in 1941.

Theodor Hänsch becomes full professor at Stanford, where he works with Art Schawlow for another elven years. In the meanwhile, Schawlow receives the Nobel Prize for laser spectroscopy in 1981.

In 1970, he leaves Germany to join Arthur Schawlow, co-inventor of the laser, at Stanford. There he invents a laser with a very high spectral resolution (i.e. all the photons emitted had nearly the same energy, to within one part in a million).

He studies physics at the University of Heidelberg, becoming intrigued by lasers which had been invented a few years earlier. For his experimental diploma thesis, he already does research on gas lasers.

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