Experimental and theoretical observations of the slow-light effect on a tunable photonic crystal

Abstract

available online at http://www.opticsinfobase.org/abstract.cfm?URI=josab-24-6-1416International audienceWe describe how the susceptibility of a nonlinear material, such as lithium niobate, can change when the material is nanostructured. Indeed, we show, by the calculation of the local-field factor inside a photonic crystal, a significant augmentation of the susceptibility, especially at the edges of the photonic bandgap. In addition, and for the case of lithium niobate, we observe an increase of the second-order nonlinear coefficient. The experimental realization of an electro-optic tunable photonic crystal, based on a square lattice of holes, shows that the measured phenomenon completely agrees with the theoretical predictions

Enhanced electro-optic modulation of LiNbO$_{3}$-based photonic crystal cavities with dual mode and polarization operation

“…The optical field highly concentrates inside and in the vicinity of the cavity region. The effective electro-optic coefficient in a structured material depends on the local field factor [29]. The local field factor, f , is defined by…”

Slow-Light Optimization of Polymer-Infiltrated Slot Photonic Crystal Waveguide

“…5 illustrates the configuration of dynamic modulation in the optimized PI-SPCW (r = 0.30a, d = 0.32a, y1 = 0.020a, y2 = 0.080a, and a = 341 nm). Two electrodes have been placed on each side of the waveguide, which means that the electrostatic field lines are parallel to the y axis, allowing the largest electro-optic coefficient γ 33 in polystyrene to be used [24]. In the simulations, the relationship between the variation in the refractive index of polymer and the external driving voltage can be generally calculated as [13] …”

“…This physical condition imposes a restriction on the amount of fluid to be infiltrated, affecting directly the effective refractive index changes of the infiltrated air holes and introducing an extra challenge to the optimization of SPCW based on fluid infiltration. To realize the dynamic modulation of photonic crystal devices, several physical effects have been made on post-fabrication schemes, such as electro-optic effect [24], acousto-optic effect [25], thermo-optic effect [26], and magneto-optic effect [27]. Among which the electro-optic effect has the highest response speed of the order of nanosecond, and the electro-optic effect can be greatly increased when the slow light phenomenon is introduced to improve the light-matter interaction.…”

Switchable photonic crystal cavity by liquid crystal infiltration

“…Widely used as filters [3] thanks to the band gap effect that PhCs present, they are, nowadays, at the heart of large range of integrated optical components such as modulators [4]- [6], switches [7], and superprisms [8]- [10] for multiplexing and demultiplexing for example. At the same time, the tunability of these devices appears as a challenge and different techniques have been used in order to make active photonic crystals, such as acousto [11] or electro-optic [12] effects, nonlinear properties of the materials or thermal [13] effects. Tuning resonant peak by modifying the cavity hole geometry and infiltration of liquid crystals has already been observed [14].…”