Dynamical Symmetry and Generation of Squeezed States of Light

Peng Liu, Juan Li, Xiao Xiang +4 more

The squeezed state, as an important quantum resource, has great potential applications in quantum computing, quantum communication and precision measurement. In the noncritically squeezed light theory, the predicted noncritically squeezed light can be generated by breaking the spontaneous rotational symmetry occurring in a degenerate optical parametric oscillator (DOPO) pumped above threshold. The reliability of this kind of squeezing is crucially important, as its quantum performance is robust to the pump power in experiment. However, the detected squeezing degrades rapidly in detection, because the squeezed mode orientation diffuses slowly, resulting in a small mode mismatch during the homodyne detection. In this paper, we propose an experimentally feasible scheme to detect noncritically squeezing reliable by employing the spatial mode swapping technic. Theoretically, the dynamic fluctuation aroused by random mode rotation in the squeezing detection can be compensated for perfectly, and 3 dB squeezing can be achieved robustly even with additional vacuum noise. Our scheme makes an important step forward for the experimental generation of noncritically squeezed light.

Serge Reynaud, A. Heidmann

Na 娜 Li 李, Zi-Jian 资鉴 Lin 林, Mei-Song Wei +4 more

It is well known that squeezed states can be produced by nonlinear optical processes, such as parametric amplification and four wave mixing, in which two photons are created or annihilated simultaneously. Since the Hamiltonian of the dynamic Casimir effect contains a 2 and a +2, photons in such a process are also generated or annihilated in pairs. Here we propose to get squeezed light through the dynamic Casimir effect. Specifically, we demonstrate it from the full quantum perspective and the semiclassical perspective successively. Different from previous work, we focus on generating squeezed states with the lowest average photon number, because such squeezed states have better quantum properties. For the full quantum picture, that is, phonons also have quantum properties, when the system is initially in the excited state of phonons, squeezed light cannot be generated during the evolution, but the light field can collapse to the squeezed state by measuring the state of phonons. When the phonon is treated as a classical quantity, that is, the cavity wall is continuously driven, squeezed light with the minimum average photon number will be generated in the case of off-resonance. This will play a positive role in better regulating the photon state generated by the dynamic Casimir system in the future.

Harry J. Kimble

A. A. Bakasov, B.M. Narbaev

One of the realistic models of the squeezed state generation in the four-wave mixing has been discussed. An asymptotic stability of the generation regime of the light dynamic squeezing is strictly shown. The absence of the periodic bifurcation for the experimental parameter values reveals that the multifrequency generation of the squeezed light has not taken place.

Harry J. Kimble, Robert J. Brecha, Luis A. Orozco +3 more