A four-wave-mixing source of low-frequency squeezed light

Meng-Chang Wu, Travis Horrom, Brian Anderson +1 more

Prem Kumar, Mikhail I. Kolobov

Meng-Chang Wu, Travis Horrom, Brian Anderson

Rong Ma, Wei Liu, Zhongzhong Qin +4 more

Using a nondegenerate four-wave mixing (FWM) process based on a double-Λ scheme in hot cesium vapor, we demonstrate a compact diode-laser-pumped quantum light source for the generation of quantum correlated twin beams with a maximum squeezing of 6.5 dB. The squeezing is observed at a Fourier frequency in the audio band down to 0.7 kHz which, to the best of our knowledge, is the first observation of sub-kilohertz intensity-difference squeezing in an atomic system so far. A phase-matching condition is also investigated in our system, which confirms the spatial-multi-mode characteristics of the FWM process. Our compact low-frequency squeezed light source may find applications in quantum imaging, quantum metrology, and the transfer of optical squeezing onto a matter wave.

Colin F. McCormick, Alberto M. Marino, Vincent Boyer +1 more

We demonstrate the use of four-wave mixing in hot atomic vapor to generate up to -7.1 dB of measured relative-intensity squeezing. Due to its intrinsic simplicity, our system is strongly decoupled from environmental noise, and we observe more than -4 dB of squeezing down to frequencies as low as 5 kHz. This robust source of narrowband squeezed light may be useful for a variety of applications, such as coupling to atomic ensembles and enhancing the sensitivity of photothermal spectroscopy.

Hudson A. Loughlin, Álvaro Fernández-Galiana, Masaya Ono +5 more