Optoelectronics and Sol-Gel

The rapidly increasing market for optical communications is placing an ever-increasing demand on the laser light source. Non-linear optical materials are being used to expand the frequency capabilities of a range of laser sources. Currently, non-linear optical materials are based on solid state materials such as KTP (potassium titanyl phosphate). Organic dyes are the next generation of non-linear optical materials due to the fact that they can be tuned to give particular frequency outputs. Current technology for these dyes involves complex and cumbersome pumping mechanisms. Incorporating these dyes into solid matrices is seen as the next step forward. Encapsulation of the optical active dyes allows the pumping system to be dispensed with and the production of simple but robust devices.

Organic dye immobilisation

The immobilisation of the dye in a transparent solid host would allow the potential of the dyes to be exploited for several reasons:

• Fabrication of simple non-linear optical devices
• Signal enhancement
• Enhances dye lifetime
• Improved output signal flexibility

Sol-gel matrices

One type of matrix that can be used is within sol-gel derived materials. Sol-gel synthesis can be used to fabricate a range of materials, such as:

• Porous inorganic networks, either films or monoliths
• Inorganic/organic hybrid materials
• Inorganic/organic nanocomposite materials

Near net shape monoliths can be fabricated using sol-gel derived materials. The pore size distribution can be tailored to match the size of the dye molecule and therefore enhance the important dye/matrix interactions.

Conclusions

Tuneable organic dyes have the flexibility of response to give them a significant advantage over other non-linear optical materials. Encapsulation of these materials into a solid matrix improves the response of these materials as well as increasing their lifetime. The development of a single, simple device based on these dyes would rapidly accelerate their industrial importance.

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