Backward traveling wave optical parametric interactions

E. Brambilla, A. Gatti, Luigi A. Lugiato +1 more

Andrei I. Maimistov, Ashat M. Basharov

Hsiung Hsu

Parametric interactions are excited by reactive (imaginary) interaction energy. When the scattering involves backward traveling-waves, the interaction will exhibit phase conjugation characteristics. There are significant differences between forward and backward phase conjugation processes.

Kaidong Peng, Mahdi Naghiloo, Jennifer Wang +3 more

Simultaneous ideal quantum measurements of multiple single-photon-level signals would advance applications in quantum information processing, metrology, and astronomy but require the first amplifier to be simultaneously broadband, quantum limited, and directional.However, conventional traveling-wave parametric amplifiers support broadband amplification at the cost of increased added noise and are not genuinely directional due to non-negligible nonlinear backward-wave generation.In this work, we introduce a new class of amplifiers that encode the information in the Floquet modes of the system.Such Floquetmode amplifiers prevent information leakage and overcome the trade-off between quantum efficiency (QE) and bandwidth.Crucially, Floquet-mode amplifiers strongly suppress the nonlinear forward-backward wave coupling and are therefore genuinely directional and readily integrable with qubits, clearing another major obstacle toward broadband ideal quantum measurements.Furthermore, Floquet-mode amplifiers are insensitive to out-of-band impedance mismatch, which otherwise may lead to gain ripples, parametric oscillations, and instability in conventional traveling-wave parametric amplifiers.Finally, we show that a Floquet-mode Josephson traveling-wave parametric amplifier implementation can simultaneously achieve > 20 dB gain and a QE of η/η ideal > 99.9% of the quantum limit over more than an octave of bandwidth.The proposed Floquet scheme is also widely applicable to other platforms, such as kinetic inductance traveling-wave amplifiers and optical parametric amplifiers.

Jiajin Lu, Minjie Wang, Haole Jiao +4 more

The enhancement of atom-photon interactions with F-P cavities provides a suitable platform for studying quantum optics and atomic physics. However, the emission fields in linear F-P cavities are in the standing-wave mode, which leads to non-uniform atom-photon coupling and a short storage lifetime of cavity-enhanced spin-wave quantum storages. This study experimentally demonstrates traveling-wave atom-light interactions in an F-P cavity that can preserve light helicity. First, a bias magnetic field is applied along the z-axis to define the quantization axis, which lifts the Zeeman degeneracy and breaks the time reversal symmetry. Next, non-classically correlated pairs of Stokes photons and spin waves are produced based on the Duan-Lukin-Cirac-Zoller scheme. The Stokes photons initially emitted from a single circularly polarized atomic transition have left-and right-hand circular polarizations when propagating along the +z (forward) and -z (backward) directions, which are preserved in the chiral cavity within the atom-photon interaction region. Thus, when the forward and backward Stokes fields resonate with the cavity, they may interact with the atoms in a traveling-wave manner. This is confirmed by measuring the time-dependent retrieval efficiencies of spin waves correlated with the forward and backward Stokes fields. This work paves the way for demonstrating traveling-wave atom-photon interactions in F-P cavities.