The effect of structural disorder on guided resonances in photonic crystal slabs studied with terahertz time-domain spectroscopy

Abstract

We measure the normal-incidence transmission coefficient of photonic crystal slabs with hexagonal arrays of air holes in silicon. The transmission spectra exhibit sharp resonant features with Fano line shapes. They are produced due to the coupling of the leaky photonic crystal modes, called guided resonances, to the continuum of free-space modes. We investigate the effects of several types of structural disorder on the spectra of these resonances. Our results indicate that guided resonances are very tolerant to disorder in the hole diameter and to interface roughness, but very sensitive to disorder in the lattice periodicity.

Characterization of photonic bands in metal photonic crystal slabs

“…To study photonic band, we employ an out-of-plane illumination scheme ( Fig. 1(b)), which is similar to the experimental setup of the silicon PC [3,4]. The ΓM and ΓK directions are also shown in Fig.…”

“…Lots of research focused on the transmission properties for out-ofplane propagations through silicon PC due to the low loss property of silicon in THz range. From the angular variation of the transmission spectra, the photonic band structure for the guided resonances can be found, which can benefit to the development of photonic devices [2][3][4][5]. Compared with the silicon PC, the metal PC slabs (also called metal holes array, MHA) show the unique characteristics in the microwave and THz range due to their influence on the electric field of electromagnetic wave.…”

Out-of-Plane Propagation in Photonic Quasi-Crystals: Guided Resonances

“…Although it is known that they are intrinsically robust with respect to the hole size imperfections and interface roughness in the PC slab (thereby resulting in a higher yield for a given fabrication process), 23 it was also demonstrated that structural random disorder in the hole positions strongly broadens the resonant line shapes in the transmission spectrum, up to their complete disappearance 23 (see Fig. 4).…”

Terahertz Sensor Using Photonic Crystal Cavity and Resonant Tunneling Diodes

“…A PC is composed of dielectric materials with a periodic refractive index distribution. In the THz region, PC slabs [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] and their applications such as planar low-loss waveguide have been demonstrated [32]. High-Q THz PC micro-cavities (approximately 1000-9000) [25,29,30,34] and their applications in sensing have been recently reported [30,34].…”