Method and apparatus for the synthesis of electromagnetic radiation
The invention relates to a method for the synthesis of electromagnetic radiation, wherein electromagnetic radiation having a spectrum comprising two or more spectral components is generated and phase setting of the electromagnetic radiation is performed. The invention proposes that the phase setting comprises phase shifting of the spectral components of the electromagnetic radiation, wherein the relative phase relationship of the spectral components is predeterminable. In addition, the invention relates to an apparatus for the synthesis of electromagnetic radiation, said apparatus comprising a pulsed laser ( 1 ), which generates a sequence of temporally equidistant light pulses, wherein the spectrum of the electromagnetic radiation of the pulsed laser ( 1 ) is the spectrum of an optical frequency comb, which is characterized by an offset frequency and a repetition rate. Furthermore, the apparatus has a phase setter ( 5 ), which effects phase setting of the electromagnetic radiation of the pulses laser ( 1 ). In accordance with the invention, the offset frequency of the spectral lines of the optical frequency comb is adjustable by time-proportional phase setting by means of the phase setter ( 5 ).
1. An apparatus for synthesis of electromagnetic radiation, said apparatus comprising:
a source of light generating electromagnetic radiation, the spectrum of which comprises a plurality of spectral components, and
a phase setter, which effects phase setting of the electromagnetic radiation of the source of light,
wherein the phase of at least some of the spectral components of the electromagnetic radiation can be shifted by means of the phase setter, and wherein the phase setter comprises at least one splitter element which effects a temporal and/or spatial splitting of the spectral components of the electromagnetic radiation, wherein at least one phase setting actuator of the phase setter comprises a medium which effects a temporally and/or spatially variable phase shifting of the electromagnetic radiation.
2. The apparatus according to claim 1 , wherein the source of light is a pulsed laser, which generates a sequence of temporally equidistant light pulses, wherein the spectrum of the electromagnetic radiation of the pulses laser is the spectrum of an optical frequency comb, which is characterized by an offset frequency and a repetition rate, wherein the offset frequency of the spectral lines of the optical frequency comb is adjustable by means of the phase setter by time-proportional phase setting, wherein the repetition rate essentially remains constant.
3. The apparatus according to claim 2 , comprising a controller actuating the phase setter, said controller stabilizing the frequency of at least one of the spectral components of the optical frequency comb.
4. The apparatus according to claim 3 , comprising an f-2f-interferometer arranged downstream of the phase setter, wherein the controller derives a controlling variable from the output signal of the f-2f-interferometers.
5. The apparatus according to claim 2 , wherein the phase setter comprises at least two phase setting actuators which in the beam trajectory of the electromagnetic radiation are arranged one behind the other and which have a different dispersion.
6. The apparatus according to claim 5 , wherein the phase actuators are electro-optical modulators.
7. The apparatus according to claim 1 , wherein the phase setter comprises at least one compensating element which wholly or partly overrides a temporal and/or spatial splitting of the spectral components of the electromagnetic radiation.
8. The apparatus according to claim 1 wherein the splitting element and a compensation element each further comprise a spatially or temporally dispersive element.
9. The apparatus according to claim 1 , wherein the phase setter is located wholly or partly outside the optical resonator of the pulsed laser.