相干光与空间反演对称介质作用的压缩性质

分析研究了相干光与具有空间反演对称非线性介质作用的压缩性质。对于一种非线性介质 ,其势能具有空间反演对称性 ,在此情况下介质的偶次极化率为零 ,对介质极化起主导作用的是它的三次极化率。因此 ,单模光场与此介质相互作用的哈密顿量正比于光场的湮灭算符与产生算符和的四次方。也就是说在计算相干光通过这种具有空间反演对称介质时考虑到所有的能量非守恒项的作用。对于一单模光场 ,定义两个无量纲的正交振幅算符 ,它们分别与坐标和动量算符成正比。利用海森堡运动方程 ,得到这两个正交算符的方程 ,并算出其近似解 ,然后计算这两个量的量子涨落。结果表明 ,可通过调节耦合常数、入射平均光子数、入射光频率、相互作用时间等参数来控制光场振幅算符分量的压缩性质

Squeezing Property of Coherent Light Coupled to a Nonlinear Medium of Inversion Symmetry

An analytical approach is adopted for the calculation of squeezed property of coherent light interacting with a nonlinear medium of inversion symmetry. A medium is called inversion symmetric if the potential energy remains invariant under parity transformation. Thus the even order susceptibilities would vanish for the medium and the leading contribution to the nolinear polarization due to the medium is the third order susceptibility. Therefore interaction Hamitonian of the single mode light field with the medium is proportional to the fourth power of the annihilation operator plus creation operator. This means is to take care all the non conserving energy terms for the calculation of the squeezing property of coherent light passing through the nonlinear medium of inversion symmetry. For a single mode light, two dimensionless quadrature operators are defined which are proportional to the usual position and momentum operators respectively. Using the Heisenberg operator equation of motion, the differential equation of the quadrature operators and the approximate solutions to the equations are got. Then the quantum fluctuations of the two quadratures are calculated. The result shows that the squeezing property of the two quadrature operators is controllable through changing the following parameters: coupling constant, mean photon number, light field frequency, and interaction time.