Frequency Combs
Frequency combs are generated from modelocked lasers. However, normally these frequency combs are not stable and need additional stabilization. There are two degrees of freedom: comb spacing (i.e. pulse repetition rate) and comb offset (i.e. carrier envelope offset phase or also referred to as carrier envelope phase).
The comb spacing was stabilized before in the 1980's (referred to as "timing jitter stabilization")
DownloadPatent D. Cotter 1985 (PDF, 418 KB) (and Ultrafast Phenomena IV, 1984)
DownloadActively modelocked flashlamp-pumped Nd:YAG laser (PDF, 2.2 MB) in Prof. Dave Bloom's group Standord University (1986 and 1989)
We proposed in collaboration with Dr. Telle (PTB, Braunscheig) how to do the comb offset stabilization, which was not obvious. For example we proposed both the f-to-2f and the 2f-to-3f heterodyne technique, which are being used today and published in DownloadRef. [113] (PDF, 258 KB)
Our pioneering contribution to this field was also recognized by the Nobel committee for the Physics Nobel Prize in 2005 (see page 11, Ref. [37], DownloadAdvanced Information for the Nobel Prize in Physics 2005 (PDF, 575 KB)
