Hansch, Theodor Wolfgang, << hehnsh, TAY oh dohr VAWLF gahng >> (1941-…), a German physicist, shared the 2005 Nobel Prize in physics with the American physicists John L. Hall and Roy J. Glauber. Hansch and Hall won the prize for developing improved methods of using lasers to make measurements. Glauber won for devising a mathematical model of light used in a branch of physics called quantum mechanics.
Hansch’s research involves using lasers to precisely measure frequencies of light. The frequency of light equals the number of times per second that the crest of a light wave passes a stationary point. Most light sources produce light with a wide range of frequencies. These frequencies form a band called a spectrum (plural spectra). Throughout his career, Hansch has used lasers to precisely measure the frequencies of light emitted by atoms as they undergo internal changes. These measurements have helped scientists refine models of the structure and behavior of subatomic particles, the smaller pieces of matter that make up atoms. Hansch’s measurements have also aided in the development of more precise standards of time and length based on frequencies of light.
Hansch developed a method of measuring frequency called the optical frequency comb technique. This method combines pulses from a laser to produce light made up of regularly spaced peaks in frequency. The term frequency comb refers to the spectrum of this light, in which the narrow peaks resemble the teeth of a haircomb. We measure the length of everyday objects by comparing them to the evenly spaced marks on a ruler. Similarly, physicists can measure the frequency of light by comparing it to the evenly spaced peaks on a frequency comb.
Hansch began developing the ideas behind the optical frequency comb technique as early as the late 1970’s. Hall produced many advances in laser technology that enabled physicists to produce the frequency comb and use it in measurement. The work of Hansch and Hall led to the first optical frequency comb measurements, taken in the late 1990’s.
Hansch was born on Oct. 30, 1941, in Heidelberg, Germany. He received his doctorate in physics from the University of Heidelberg in 1969. He worked as a professor at Stanford University in California from 1972 to 1986. That year, he returned to Germany to become the director of the Max Planck Institute of Quantum Optics in Garching and a professor at Ludwig-Maximilians University in Munich.
See also Glauber, Roy Jay ; Hall, John Lewis ; Spectrum .
