Electrical tuning of photonic crystals infilled with liquid crystals

Liquid Crystals into Planar Photonic Crystals

“…1, the optical response of a PhC infiltrated with nematic LCs can be adjusted by applying an external electric field that modifies the molecule orientation inside the holes (Maune et al, 2004;Alagappan et al, 2006;Haurylau et al, 2006a-b;Anderson et al, 2007;Reyes et al 2008). Since semiconductor materials like InP are usually characterized by small electro-optic coefficients (Scrymgeour et al, 2003), this latter mechanism is particularly interesting when relatively moderate electric fields are used for the tuning of the optical properties of semiconductor-based planar PhCs.…”

“…Finally, when nematic LCs are mixed with photosensitive molecules like photochromes (see below), the latter phase transition can be photoinduced isothermally by light irradiation at certain wavelengths. All these tuning mechanisms are reversible and they have been exploited to tune the optical properties of PhC structures infiltrated with nematic LCs (Alagappan et al, 2006;Halevi et al, 2006;Haurylau et al, 2006a-b;Martz et al, 2006;Anderson et al, 2007;Reyes et al, 2008). In this chapter, we will show how the infiltration of LCs in the air holes of III-V semiconductor-based planar PhCs can be used to both trim and tune the optical properties of PhC devices by controlling the orientation of the LCs inside the nanometer-size holes by means of a temperature, electrical or optical trigger.…”

Evolution of complete photonic band gap in anisotropic photonic quasicrystals using liquid crystals

“…In 1999, Bush and John proposed that by infiltrating three dimensional (3D) PCs with liquid crystal (LC), an applied electric field would tune the PBG (11). Following this publication, some investigations of band gap tunability have been done by utilizing LCs in one-dimensional (1D) (12)(13)(14)(15), two-dimensional (2D) (16)(17)(18)(19)(20), and three-dimensional (3D) (21)(22)(23) PCs.…”

Electro‐tuning of surface state in two‐dimensional photonic crystals

“…Recently, we have reported on the tuning of defect modes in 2D PCs in which defect formed with nematic LC inclusion 3. Electrical tuning of 2D photonic crystals (PCs) infilled with liquid crystals has been completely studied by Reyes et al a few years ago 7. They have included the configuration of the NLC directors in the band structure calculation for the first time with assuming DC tuning field applied in the axial (AX) direction.…”

“…The alignment of NLC directors plays an important role on the position of surface states inside photonic band gap (PBG). The configuration has been obtained by minimizing the total [elastic plus electromagnetic (EM)] free energy 7. Although, the slab (PCs) is practically important, in order to get some insight, in this work we consider an ideal 2D square lattice PC of circular air holes in alumina background in which one row of the outermost air holes is infiltrated by NLC.…”