Babić Lj, de Dood M J A
Huygens Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands.
Opt Express. 2010 Dec 6;18(25):26569-82. doi: 10.1364/OE.18.026569.
Resonant coupling of light to leaky modes of a photonic crystal slab leads to asymmetric Fano lineshapes in the reflectivity spectra. The generally accepted picture, for a lossless system, is that the sign of the real-valued parameter q controls the asymmetry of a Fano resonance. For the reflectivity of a symmetric slab this situation occurs if the amplitude reflection coefficient of the slab goes through zero. In this article, we show that it is also possible to change the asymmetry of a resonance by angle tuning without reaching a condition of zero amplitude. Moreover, we show that the picture of a real-valued parameter q that controls the asymmetry is incomplete.
光与光子晶体平板的泄漏模式的共振耦合导致反射光谱中出现不对称的法诺线形。对于无损系统，普遍接受的观点是实值参数q的符号控制着法诺共振的不对称性。对于对称平板的反射率，当平板的振幅反射系数为零时会出现这种情况。在本文中，我们表明，在不达到振幅为零的条件下，也可以通过角度调谐来改变共振的不对称性。此外，我们表明，用实值参数q来控制不对称性的观点是不完整的。
