d) A Second, Stable Laser
A laser locked to one of the above mentioned references can serve as a reference itself. Difference frequencies are limited by the bandwidth of the employed photodetector,
The concept of phase and frequency stabilization relies on the possibility to detect changes of the quantity that is wished to be stabilized. To do so this quantity has to be measured continuously,
a) Atomic or Molecular Transitions – Spectroscopy
For many applications, a good and simple way to stabilize a laser´s frequency is to compare it to an atomic or molecular transition. One advantage
b) Optical Cavities
An alternative approach of measuring a laser´s frequency is to link it to the geometrical properties of an optical cavity. The most common type for this purpose is the
c) Frequency Comb
Another way to stabilize a laser´s phase or frequency is to compare it to a stable light source. A tool which has been developed for exactly this purpose is the frequency comb. Its
TOPTICA Solution
The TOPTICA DFC CORE + is a frequency comb which is based on Difference Frequency Generation (DFG), i.e. the carrier-envelop offset is passively fixed to \(f_{CEO}=0\). It is
There are various ways to lock a laser to another optical reference. Here, the general principle of a phase lock to an optical reference will be described. The optical reference can e.g. be a second