Photonics: Science that involves the generation, manipulation, propagation, and detection of light. Photonics deals with using light for the control of information processing.
Dow Corning's Photonic Technology
Silicone-based materials are stable to environmental effects, such as degradation caused by heat and ultraviolet (UV) radiation, and can be designed with the different refractive indices required for various optical applications.
Silicon-based materials provide a wide range of refractive indices for optical applications.
In addition, optical properties where refractive index changes are effected either thermally (thermo-optic) or electrically (electro-optic) can be incorporated in silicon-based materials. These unique combinations of physical, chemical, and optical properties allow silicon-based materials to be the premier candidate for the construction of optical components.
Polymer Waveguides
Siloxane polymers have many attributes that make them viable materials of choice for polymer waveguides, which are devices that direct and control the propagation of light. Polymer waveguides can be spin-coated from uncured precursors or polymer solutions as uniform coatings that are then patterned into the specific waveguide geometries using either reactive ion etch (RIE) or direct exposure to UV light patterns (if the material is UV curable). Precise control of the refractive index of both the core and the cladding material allows one to optimize the light transmission through the waveguide.
These propagation loss values in optical waveguide materials were obtained on various polymers using the Optical Solutions NIR fiber optic spectrometer. The values were calculated from vibrational infrared absorption data for various siloxane-based polymers and resins with different chemical substituents.
Electro-Optics
The optical properties of siloxanes, which can be adjusted by controlling their molecular structure with specific chemical synthesis steps, also make them interesting matrix materials for various "guest" molecules, such as liquid crystals. Their properties include a wide range of refractive index and thermo-optic coefficient, as well as very low birefringence. By combining siloxanes with liquid crystals, one can create materials to manipulate light and fabricate devices for use in a variety of photonic applications. The liquid crystal provides a means of introducing electro-optic tuning.
Here is an induced degree of circular polarization created by a siloxane-based, polymer-dispersed liquid crystal (PDLC) sample. This experiment illustrates the potential for siloxane-based, polymerization-induced, phase-separated (PIPS) materials to provide polarizatioin manipulation in photonic devices. The sample is behaving as a variable wave plate, acting on a linearly polarized input beam. The response of the devise is proportional to the applied electric field, which ranges up to ~10 V / μm. The solid line is a quadratic fit to the data points.
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Sources:
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A. Norris, J. DeGroot, F. Nishida, U. Pernisz, N. Kushibiki, T. Ogawa, "Linear and Nonlinear Optics of Organic Materials II," Proc. 47th Annual SPIE Conference, 4798, p79-86 (2002).
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H. Coles, J. Hannington, D. Thomas, US5,455,697 (10/3/1995).
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H. Coles, J. Hannington, D. Thomas, US5,547,604 (8/10/1996).
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