Narrow-band readout and compression of a single acousto-optic frequency comb using digitally enhanced heterodyne interferometry

We present an acousto-optic frequency comb readout scheme synthesized from multiple intra-comb beat measurements using digitally enhanced heterodyne interferometry. The readout scheme enables a single acousto-optic frequency comb to achieve a compression factor, which normally requires a dual comb measurement scheme. We demonstrate an absorption measurement of the 2<i>ν</i>₃ P10 <i>H</i>¹³<i>C</i>¹⁴<i>N</i> line obtaining a noise equivalent absorption sensitivity of 1.75 × 10^-8cm^-1Hz^-1/2. Additionally we demonstrate the ability of the system to software-adjust the compression factor to access a wider optical bandwidth.