Liu Guanghui, Cao Yanan, Liu Renming, Chen Gengyan, Wu Feng, Zheng Yunbao, Chen Zhanxu, Guo Kangxian, Lu Liangliang
Opt Express. 2022 Feb 14;30(4):5200-5212. doi: 10.1364/OE.445059.
An intense terahertz laser field is shown to actively manipulate the electronic states, as well as the linear and nonlinear optical absorption coefficients, of the laterally-coupled quantum well wires (LCQWWs). The laser-dressed quantum states of the LCQWWs are achieved using the non-perturbative Floquet method and the two-dimensional diagonalization technique under the effective mass approximation. We have demonstrated that the intense terahertz laser field induces a strong deformation of the confinement potential configuration of the LCQWWs, thus pronouncedly dressing the energy levels and wave functions. An unambiguous picture is depicted for the evolution of the laser-dressed quantum states with the increase of the laser-dressed parameter characterizing the strength of the laser-dressed effect. On this basis, the resonant peak positions of the linear and nonlinear optical absorption coefficients feature a blue shift followed by a red shift with an increase of the laser-dressed parameter. Furthermore, the evolution of the peak values for the linear and third-order nonlinear optical absorption coefficients as a function of the laser-dressed parameter is comprehensively discussed. Moreover, in contrast to the case without intense terahertz laser field, the peak values of the linear, third-order nonlinear, and total optical absorption coefficients can be obviously enhanced at the same frequency position by manipulating the appropriate laser-dressed parameter. A similar feature can be found in the linear, third-order nonlinear, and total refractive index changes. Our findings are conducive to the implementation of the expected quantum states and nonlinear optical effects in the LCQWWs, paving the way for new designs in tunable optical switches, infrared photo-detectors and infrared modulators.
研究表明，强太赫兹激光场能够积极操控横向耦合量子阱线（LCQWWs）的电子态以及线性和非线性光学吸收系数。在有效质量近似下，利用非微扰弗洛凯方法和二维对角化技术实现了LCQWWs的激光修饰量子态。我们已经证明，强太赫兹激光场会引起LCQWWs限制势构型的强烈变形，从而显著修饰其能级和波函数。描绘了随着表征激光修饰效应强度的激光修饰参数增加，激光修饰量子态的演化的清晰图像。在此基础上，线性和非线性光学吸收系数的共振峰位置随着激光修饰参数的增加呈现先蓝移后红移的特征。此外，还全面讨论了线性和三阶非线性光学吸收系数的峰值随激光修饰参数的演化。而且，与没有强太赫兹激光场的情况相比，通过操控适当的激光修饰参数，可以在相同频率位置明显增强线性、三阶非线性和总光学吸收系数的峰值。在线性、三阶非线性和总折射率变化中也能发现类似特征。我们的研究结果有助于在LCQWWs中实现预期的量子态和非线性光学效应，为可调谐光开关、红外光电探测器和红外调制器的新设计铺平了道路。
