Two-photon (squeezed) light: Classical and quantum effects

L. Sáinz de los Terreros, Francisco Javier Bermejo

Shou Zhang

The quantum properties of light in the system of two different atoms interacting with two-mode squeezing vacuum field are studied.The effect of the relative coupling constant(R=g1/g2) and initial squeezed parameter r on light squeezing effect and the photon bunching and antibunching are discussed.The numerical results show that vibration range of quantum fluctuation,the biggest squeezing depth and squeezing time and vibration amplitude of second-order coherence is affected by the initial squeezed parameter r.The variation of quantum fluctuation and second-order coherence versus time are affected by the relative coupling constant R.As a result,the squeezing time of quantum fluctuation,the time when light field is in non-classical states and the degree of photon antibunching are also affected by it,but to but it doesn′t have obvious influence on light squeezing depth.

H Lotfipour, Z Allameh, R Roknizadeh +1 more

Abstract Using two different schemes, a non-classical-squeezed state of light is detected and characterized. In the first scheme, in a one-dimensional cavity with a moving mirror (non-stationary Casimir effect) in the principal mode, we study the photon generation rate for two modes (squeezed and coherent state) of a driving field. Since the cavity with the moving mirror (similar to an optomechanical system) can be considered an analogue to a Kerr-like medium, in the second scheme, the probability amplitude for multi-photon absorption in a nonlinear (Kerr) medium will be quantum mechanically calculated. It is shown that because of the presence of nonlinear effects, the responses of these two systems to the squeezed versus coherent state are considerably distinguishable. The drastic difference between the results of these two states of light can be viewed as a proposal for detecting non-classical states.

Dan Yao, Guang‐Can Guo

Carlton M. Caves

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.