Patent ID: 8515290

Claim:
Method for coupling a first laser ( 1 ) and second laser having an adjustable difference of their pulse frequencies, which is not equal to zero, wherein the method comprises the following steps: derivation of a first harmonic signal and a signal of the M th harmonic from the time progression of the light intensity of the pulses emitted by the first laser, mixing of the first harmonic signal and the signal of the M th harmonic, in order to obtain a first mixed signal, derivation of a second harmonic signal from the time progression of the light intensity of the pulses emitted by the first laser or from the time progression of the light intensity of the pulses emitted by the second laser and a signal of the N th harmonic from the time progression of the light intensity of the pulses emitted by the second laser, mixing of the second harmonic signal and the signal of the N th harmonic, in order to obtain a second mixed signal, wherein the first and second harmonic signal and the M th and N th harmonic are selected in such a manner that the frequencies of the first and second mixed signal are identical, wherein the method furthermore comprises: regulation of the pulse frequency and pulse delay of the first laser in a closed phase-locked loop, in such a manner that the relative phases of the first and second mixed signal remain constant, in terms of time, and the frequencies of the first and second mixed signal remain identical.