Quantum coherence of light and precision measurement of optical frequency—an introduction to the 2005 nobel prize in physics

The Nobel prize in physics 2005 was awarded to Roy J. Glauber for “his contribution to the quantum theory of optical coherence” and to John L. Hall and Theodor W. Hnsch “for their contributions to the development of laser-based precision spectroscopy, including the optical frequency comb technique”. A brief introduction to their work and the significance of their contributions is presented