在对激子不作任何近似的条件下,对强耦合激子声子系统中非线性光学性质在理论上进行了研究,结果表明当信号光场频率与激子频率的失谐量等于光学声子的频率时,系统的非线性光学吸收和克尔系数显著增大,从而证明了激子声子的强相互作用对介质的非线性光学性质的影响相当大。并且,与对激子作代松马利夫(Dyson-Maleev)变换近似和玻色近似的结果进行仔细的比较,发现对激子不作近似时,这种影响将进一步增大。

The nonlinear optical properties of the strongly coupled exciton-phonon systems are investigated theoretically without making any approximation for excitons. It is shown that the nonlinear optical absorptions and Kerr coefficients are enhanced significantly as the frequency detuning value of the signal field and the excition is equal to the phonon frequency, which makes clear that the strong excition-phonon interaction affects the nonlinear optical properties of the medium greatly. The numerical results and the detailed comparison also indicate that the nonlinear optical absorptions and Kerr coefficients are further magnified without making Bose approximation and the Dyson-Maleev approximation for excitons.