Patent ID: 8564785

Claim:
A method of comb-based spectroscopy with synchronous sampling for real-time averaging comprising: generating a source comb that transmits a source pulse train through a sample to provide a signal pulse train in a time domain; generating a local oscillator (LO) comb that transmits a LO pulse train at a different repetition rate in the time domain than the source pulse train so that the difference in repetition rates between the combs is Δf r ; establishing a base coherence between the source comb and the LO comb wherein each Nth pulse in the time domain from the LO pulse train has identical overlap with each Nth+1 pulse in the time domain from the source pulse train in terms of both the pulse envelope and the carrier phase; detecting the signal pulse train through linear optical sampling against the LO pulse train in which consecutive samples of an overlap between a signal pulse and a LO pulse from the LO pulse train yields a measurement of the signal pulse; digitizing the overlap between the signal pulse train and the LO pulse train synchronously with the LO pulse train; and real time summing of every Nth digitized sample to generate an averaged signal pulse.