Hybrid longitudinal-transverse phonon polaritons
Hybrid longitudinal-transverse phonon polaritons
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DOI：
10.1038/s41467-019-09414-4
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发表时间：
2019-04-11
影响因子：
16.6
通讯作者：
De Liberato, Simone
中科院分区：
文献类型：
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作者：
Gubbin, Christopher R.;Berte, Rodrigo;De Liberato, Simone
声子极化激元是由电磁场与极性晶体晶格振动的强耦合产生的混合轻物质准粒子，是中红外光子学的一个有前途的平台，但目前还没有允许其电泵浦的建议。事实上，电流主要产生纵向光学声子，而只有横向电流参与声子极化激元的产生。我们演示了如何利用碳化硅的长胞多型体来实现横向声子极化激元和带折叠纵向光学声子之间的强耦合。我们开发了一个微观理论预测所产生的混合横向激励的存在。然后，我们提供了一个实验观察，通过调谐共振的纳米柱阵列通过折叠的纵向光学模式，获得了清晰的光谱反交叉。声子极化激元与纵向声子的杂化是发展基于声子极化激元的电泵浦中红外发射器的重要一步。
Phonon polaritons, hybrid light-matter quasiparticles resulting from strong coupling of the electromagnetic field with the lattice vibrations of polar crystals are a promising platform for mid-infrared photonics but for the moment there has been no proposal allowing for their electrical pumping. Electrical currents in fact mainly generate longitudinal optical phonons, while only transverse ones participate in the creation of phonon polaritons. We demonstrate how to exploit long-cell polytypes of silicon carbide to achieve strong coupling between transverse phonon polaritons and zone-folded longitudinal optical phonons. We develop a microscopic theory predicting the existence of the resulting hybrid longitudinal-transverse excitations. We then provide an experimental observation by tuning the resonance of a nanopillar array through the folded longitudinal optical mode, obtaining a clear spectral anticrossing. The hybridisation of phonon polaritons with longitudinal phonons could represent an important step toward the development of phonon polariton-based electrically pumped mid-infrared emitters.