Acta Photonica Sinica, Volume. 42, Issue 12, 1387(2013)
Modulation Instability in Metamaterials with Thirdorder Nonlinear Dispersion
On the basis of the extended nonlinear propagation equation without normalization in metamaterials with the firstorder to thirdorder nonlinear dispersion effects, the dispersion relation and gain spectra of modulation instability were deduced by adopting the linear stability analysis and the Drude electromagnetic model. Variations of the equation coefficients and gain spectra with the normalized angular frequencies were calculated and discussed in real units in both the positive and negative refractiveindex regions in cases of selffocusing and selfdefocusing. The results show that, the thirdorder nonlinear dispersion coefficients are all along positive in both the positive and negative refractiveindex regions. In the negative refractiveindex region, with increase of normalized angular frequencies, the spectral widths of the gain spectra increase before become zero and the peak gains increase before decrease and then become zero in the selffocusing case. While in the case of selfdefocusing, modulation instability can only occur near the forbidden band and both the spectral widths and peak gains decrease monotonically. In the positive refractiveindex region, modulation instability can only occur in the selffocusing case. And the spectral widths increase monotonically and the peak gains decrease before increase with the normalized angular frequencies. Generally, the thirdorder nonlinear dispersion is detrimental to modulation instability generation.
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ZHONG Xianqiong, CHENG Ke, XIANG Anping. Modulation Instability in Metamaterials with Thirdorder Nonlinear Dispersion[J]. Acta Photonica Sinica, 2013, 42(12): 1387
Received: Apr. 1, 2013
Accepted: --
Published Online: Dec. 16, 2013
The Author Email: Xianqiong ZHONG (zxqlxh@yeah.net)