Proprietary Electro-Optic Polymer Chemistry
What is electro-optics?
Materials are called electro-optic when they enable interactions between applied electric fields and light passing through them. Notably, they change the refractive index seen by the light with minimum loss. The result is an instantaneous and accurate conversion of an electrical signal to an optical signal. Optical signals are better for transmission over distance: an increasingly useful feature as digital signal speeds are now reaching the GHz and THz ranges and the corresponding electrical transmission distances are shrinking to meters and centimeters.
How is the polymer electro-optically active?
EO polymers are intrinsically superior in speed and sensitivity to electric field to traditional electro-optic materials such as Lithium Niobate, Indium Phosphide and Silicon. They are engineered materials, made by embedding a variety of specially designed electro-optic chromophore molecules into a wide range of standard host polymers.
Chromophores are complex, large molecules, on a scale akin to drug molecules. They are hyperpolarizable, meaning their electron clouds are easily pulled into a different shape by the applied electric field, changing their optical properties such as index of refraction.
The material is poled to become electro-optic by applying a strong electric field along with heat. The hot material is relatively soft, allowing the chromophore molecules suspended in the host polymer to align in the same direction (poling). Cooling the poled material after the molecules are in place traps them in their active state even after the poling field is removed.
Key features:
Although the electrons in the material respond to any applied electric field, they remain tightly bound to the molecule. The response to an applied signal is almost instantaneous response and recovery– like that of a tight spring– unlike materials that involve much slower macroscopic movement of free electrons.
Another key difference from traditional crystalline materials is the performance of EO polymers continues to improve as chemists explore the almost unlimited design space. Combinations of chromophores and host polymers can be tailored for specific applications.
