Real-Time Squeezed Dual-Comb Spectroscopy

The manipulation of the optical field quantum state is a promising avenue to enhance the precision and versatility of frequency comb-based measurements [1]. We recently demonstrated squeezing in dual-comb spectroscopy (DCS), showing a quantum noise reduction (QNR) of 2.9 dB and improving the determination of gas concentrations [2]. This employed a collinear DCS configuration with the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\chi^{(3)}$</tex> Kerr nonlinearity in fiber generating an amplitude squeezed state.