Photonics is concerned with the management of light. The science of photonics includes emission, transmission, amplification, detection, modulation, and switching of photons, particularly in the visible and near infra-red spectrum, but also extending to the ultraviolet, long-wave infrared, and far-infrared/THz portion of the spectrum.

Photonics is the optical equivalent of electronics, and the two technologies often coexist in such innovations as optoelectronic integrated circuits. Just as applications of electronics have expanded dramatically since the first transistor was invented in 1948, the unique applications of photonics continue to emerge. Photonic applications include data storage (using optical disks and holograms), data transmission (fiber optics), experimental optical computers, and optical power limiters, optical switches and light modulators (for signal processing and interconnection). Photonic devices include optoelectronic devices such as lasers and photodetectors, optical fiber, photonic crystals, planar waveguides, and other passive optical elements.

In an electro-optic (EO) material, an applied electric field perturbs the electron distribution of a material affecting the transmission of light through the material. The result is an electric field dependent change in the index of refraction of the material and phase shift of light. To obtain device quality materials, three stringent issues must be addressed. (a) The design and synthesis of high µβ (µ: dipole moment, β: first hyperpolarizability) chromophores and the realization of a large macroscopic EO activity in the chromophore incorporated polymer. (b) The maintenance of long-term temporal stability in the EO response of the poled materials in addition to their high intrinsic stability toward the environment (i.e., heat, light, oxygen, moisture and chemical). (c) The minimization of optical loss. Most commercially available EO devices are still made from inorganic materials such as lithium niobate. They are generally large, heavy, and very costly. Moreover, the difficulties in preparing high quality EO crystals certainly plays a major role in limiting their viability and application. The tunability of the properties of these materials is limited and generally there exists no “single crystal” that combines all of the desired characteristics for a given application.

The photorefractive (PR) effect in organic materials comprises various processes such as charge photo-generation, charge transport, and charge trapping that contributes to space-charge field formation, witha subsequent reorientation of nonlinear optical chromophores in the space-charge field. In principle, the mixing of individual components providing photosensitization, charge transport, and EO response within a polymer matrix should impart photorefractivity and allow tuning of the materials to meet the requirements of various applications. However, due to the complex nature of the effect, the design of an “ideal” material with good steady-state and dynamic PR performance as well as good thermal properties is a real challenge. The PR properties of materials are largely controlled by the polarizability and hyperpolarizability of nonlinear optical (NLO) chromophores and their poling behavior in external electromagnetic fields. Strong dipole-dipole interactions lead to a variety of instabilities, in particular, dye aggregation, crystallization and phase separation which shorten the material shelf-life, and therefore, make the material unsuitable for many applications. In order to be useful in optical device applications, a photorefractive material should be optically clear, able to adhere to surfaces and able to form good films up to several µm thick without imperfections.

Glassy inorganic materials make good matrices for organic molecules due to their physical-chemical properties, high transparency, thermal stability and high laser threshold value. The sol-gel method is a very effective low temperature route generally used to obtain inorganic glasses and ceramics. They open up great possibilities for the fabrication of novel organic-inorganic hybrid materials. MMI has recently developed a family of hyperbranched polymers (HBPs) which are processable into thin, transparent, robust and chemically stable coatings that also show excellent optical fand nonlinear optical properties. These polymers can be easily coated on substrates such as glass and metals and then can be cross-linked to form hard and transparent coatings.

Economically significant applications for photonic devices include optical data recording, fiber optic telecommunications, optical power limiting, laser printing (based on xerography), displays, and optical pumping of high-power lasers. The potential applications of photonics are virtually unlimited and include chemical synthesis, medical diagnostics, on-chip data communication, laser defense and fusion energy, to name a few interesting examples. Some of the potential military and civilian applications for photonic materials based on MMI technology include the following:

1. Holographic data storage
2. Photonics enabled satellite-to-satellite and satellite-to-aircraft data links with high transfer rates
3. Photonic control of phased-array radar of simpler architecture with reduced power and weight
4. Field dependent index of refraction materials to achieve electrical-to-optical transduction (e.g., as in the cable television industry)
5. Optical switching (e.g., for use at nodes in local area optical networks)
6. Small-angle beam steering (e.g., for addressing phosphors in flat panel displays)
7. Electro-optical modulators, potentially one of the most critical hardware components of the information superhighway
8. Photodynamic therapy