Coherent linear optical sampling at 15 bits of resolution.

Linear optical sampling characterizes a sample by measuring the distortions on a transmitted optical field, thereby quantifying the sample's optical response. By exploiting the high mutual coherence between two phase-locked femtosecond fiber lasers, we achieve very high signal-to-noise ratio measurements of transmitted optical electric fields through coherent averaging. We measure the optical electric fields with 15.16 bits of dynamic range (91 dB in intensity) and with 525 fs timing resolution over a 10 ns time window, in a 5.1 s averaging period.