Superprism Effect In Photonic Crystals Research Articles

Enhanced wavelength sensitivity of the self-collimation superprism effect in photonic crystals via slow light.

We demonstrate that the wavelength sensitivity of a self-collimation superprism in photonic crystals (PhCs) can be greatly improved via slow light. With the help of a saddle point Van Hove singularity, we present an approach to obtain such a wavelength-sensitive self-collimation superprism. Our superprism not only has extremely high wavelength sensitivity, but also can suppress beam divergence, irregular beam generation, and wavelength channel dropout, overcoming the limitations of traditional PhC-based superprisms. Based on our superprism, a high-performance compact demultiplexer is also proposed.

Direct observations for the superprism effect in photonic crystals utilizing negative refraction

In this work, we experimentally explored the negative-refraction superprism effect in photonic crystals by investigating the frequency-dependent negative refractive index of photonic crystals at microwave frequencies from 8.2to8.4GHz. By detecting the spatially distributed intensity of a transmitted microwave whose incident angle is well controlled, we determined the propagating path, the refractive angle, and the refractive index of the transmitted microwave. The highly dispersive relationship between the negative refractive index and the frequency of microwave observed indicates potential applicability of this method for being used in a microwave wavelength demultiplexer by utilizing the negative-refraction superprism effect in photonic crystals.

Tunable superprism effect in photonic crystals

AbstractWe present a review of the field of tunable superprism structures. Such structures enable an active tuning of the group propagation angle by combining the large angular dispersion near the bandgap of a photonic crystal with a tuning of the optical material properties. The tuning is significantly enhanced compared to the change of the group propagation angle in a bulk material allowing for compact devices on the sub‐millimeter scale. Tunable superprism structures can be employed for many key components of optical circuitry and optical communications. Controlled deflection or refraction of light as well as spatial beam switching are only some possible tasks such devices could accomplish. We give a survey of geometries, switching mechanisms, and materials that have been investigated theoretically or experimentally for tunable photonic bandgap (PBG) structures and tunable superprism structures. A detailed theoretical investigation is presented for all‐optical switching in a one‐dimensional tunable superprism structure employing an optically non‐linear organic material. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Second-harmonic superprism effect in photonic crystals

By exploitation of the nonlinear optical properties of two-dimensional photonic crystals, a second-harmonic superprism effect is demonstrated. The anisotropy of the dispersion curves allows control of the propagation direction of the second-harmonic field. Smooth variations of the fundamental wavelength or the angle of incidence produce a drastic angular shift of the second-harmonic emission.

Ferroelectric inverse opals with electrically tunable photonic band gap

We present a scheme for tuning the photonic band gap (PBG) by an external electric field in a ferroelectric inverse opal structure. The inverse opals, consisting of ferroelectric (Pb,La)(Zr,Ti)O3 (PLZT) ceramics, were synthesized by a sol–gel process. Optical reflection spectra show that the PBG of the PLZT inverse opals shifts continuously with the change in the applied electric field. As the photonic crystals (PCs) consist of the high-refractive-index constituent and possess an “all-solid” structure, it should supply a more reliable mode to tune the PBG by the electric field for the superprism effect in PCs. It should be of high interest in device applications.

Electro-optic control of the superprism effect in photonic crystals

We have designed a two-dimensional photonic crystal in electro-optic materials that can actively control the superprism effect. By applying an electric field to the photonic crystal, the electro-optic effect will change the dielectric constant of the material, which modifies both the band structure and the dispersion surfaces. In the proposed structures, we show that electric fields of up to 6 V/μm in (Pb0.09La0.91)(Zr0.65Ti0.35)O3-based photonic crystals can deflect light up to 49°. This device concept can be used for a class of optical modulation devices that can provide a local control of dispersion surfaces within a photonic crystal.