Duan Xueke, Zhang Fan, Qian Zhiyuan, Hao He, Shan Lingxiao, Gong Qihuang, Gu Ying
Opt Express. 2019 Mar 4;27(5):7426-7434. doi: 10.1364/OE.27.007426.
We demonstrate the spectral accumulation of large spontaneous emission (SE) for nanocavities with different sizes in the coupled Ag nanorod and epsilon-near-zero (ENZ) film system. This effect originates from the slowing down of the spectral shift of resonant nanocavities at the wavelength where the permittivity of the substrate vanishes, i.e., the resonance "pinning" near the ENZ frequency. In addition, most far field radiation of the emitter is concentrated in the forward field with small solid angle due to the impedance mismatch between the ENZ film and the free space. This kind of size-relaxed nanocavity for directional SE has potential applications in the bright single photon sources, plasmon-based nanolasers, and on-chip nanodevices.
我们展示了在耦合银纳米棒与近零介电常数（ENZ）薄膜系统中，不同尺寸纳米腔的大自发辐射（SE）的光谱积累。这种效应源于在衬底介电常数消失的波长处，共振纳米腔光谱移动的减慢，即共振“钉扎”在ENZ频率附近。此外，由于ENZ薄膜与自由空间之间的阻抗失配，发射器的大部分远场辐射集中在小立体角的前向场中。这种用于定向SE的尺寸宽松型纳米腔在明亮单光子源、基于等离子体的纳米激光器和片上纳米器件中具有潜在应用。
