Physical origin of the small modal volume of ultra-high-Q photonic double-heterostructure nanocavities
Physical origin of the small modal volume of ultra-high-Q photonic double-heterostructure nanocavities
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DOI：
10.1088/1367-2630/8/9/209
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发表时间：
2006-09
影响因子：
3.3
通讯作者：
B. Song;T. Asano;S. Noda
中科院分区：
文献类型：
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作者：
B. Song;T. Asano;S. Noda
我们最近展示了超高Q光子双异质结构纳米腔的制造，其Q因子接近100万，并且具有光波长尺寸的超小模态体积。在这里，我们描述了小模式体积的物理起源，通过分析的模式间隙的光子晶体（PC）波导，其中模式间隙效应是光子被限制在纳米腔的基本原理的（虚）色散关系。通过将不同PC波导传播模式的真实的色散关系展开为复数形式，得到了模隙的（虚）色散关系。结果表明，超小模体积来源于PC波导传播模式的反常色散关系，并可通过波导的几何参数来实现。这是证明实验的光子隧道结构的制造和测量其传输特性。这些结果对于实现具有超小模体积的高Q腔及其在纳米光子学中的应用具有重要意义。
We have recently demonstrated the fabrication of ultra-high-Q photonic double-heterostructure nanocavities with Q-factors of almost 1 million and ultra-small modal volumes with dimensions of optical wavelengths. Here, we describe the physical origin of the small modal volume by analysing the (imaginary) dispersion relations of the mode-gap of photonic crystal (PC) waveguides, where the mode-gap effect is the fundamental principle by which photons are confined in the nanocavities. By expanding the real dispersion relations of the propagation modes of different PC waveguides into their complex form, we obtain the (imaginary) dispersion relations of the mode-gap. It is shown that the ultra-small modal volume originates from the unusual dispersion relation of the propagation mode of the PC waveguide and that it can be engineered by the geometric parameters of the waveguide. This is demonstrated experimentally by the fabrication of photon tunnelling structures and measurement of their transmission characteristics. These results reported here will be very useful for the realization of high-Q cavities with ultra-small modal volumes and their application to nanophotonics.