Referencing of the beating spectra of frequency combs
AssigneeUniversite Laval
InventorsPhilippe Giaccari, Jerome Genest, Pierre Tremblay, Philippe Saucier, Jean-Daniel Deschênes
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Abstract
There is provided a method for referencing and correcting the beating spectrum generated by the interference of the components of a frequency comb source. The proposed method allows monitoring of variations of a mapping between the source and the beating replica. This can then be used to compensate small variations of the source in Fourier transform spectroscopy or in any other interferometry application in order to overcome the accuracy and measurement time limitations of the prior art. Constraints on source stability are consequently reduced.
Claims27
A method for correcting a beating interference signal, the method comprising:
- providing a frequency comb having frequency components non-uniformly distributed in a source spectrum;
- interfering the frequency components to produce the beating interference signal having a beating spectrum with beating components, the frequency comb having at least one variable frequency comb parameter;
- isolating at least one reference beating component subset among said beating components;
- monitoring at least one of a phase and a frequency of the reference beating component subset, the at least one of the phase and the frequency being related to the at least one variable frequency comb parameter;
- determining from the at least one of the phase and the frequency a correction function to be applied to the beating interference signal, the correction function to correct for a variation of the variable frequency comb parameter;
- recording the beating interference signal;
- and
- correcting a recorded beating interference signal using the correction function.
An interferometric method for analyzing a sample having a sample signature, the method comprising:
- providing a frequency comb having frequency components non-uniformly distributed in a source spectrum;
- interfering the frequency components to produce a beating interference signal having a beating spectrum with beating components, at least a portion of the beating spectrum having a relation with at least a portion of the source spectrum, the frequency comb having at least one variable frequency comb parameter, a variation of the at least one frequency comb parameter causing a variation of the relation;
- filtering at least part of the frequency comb with the sample to be analyzed to provide a sample interference signal holding the sample signature;
- recording the sample interference signal, the sample interference signal showing an error due to the variation of the at least one frequency comb parameter;
- selecting at least one reference beating component subset among said beating components;
- monitoring at least one of a phase and a frequency of the reference beating component subset, the at least one of the phase and the frequency being related to the at least one frequency comb parameter;
- determining from the at least one of a phase and a frequency a correction function to be applied to the sample interference signal, the correction function to correct for the variation of the at least one frequency comb parameter;
- and
- correcting the recorded sample interference signal using the correction function.
Dependencies are inferred from the claim text.