The future of gradient index optics

First developed over 30 years ago, gradient index lenses play an important role not only in telecommunications technology, but also in applications such as information interface and biomedical technology. Traditional manufacturing consists of doping a certain ion, A(+) into the mother glass, drawing the glass into rods and then immersing the rods into a molten salt bath containing another certain ion B+. During a thermal ion exchange process, the original ion migrates out of the mother glass, and is replaced by the alternate ion, creating a refractive index variation. Current research is being conducted to improve the thermal ion exchange technology, and open new applications. This research includes extending working distances to greater than 100 nun, decreasing the tens diameter, increasing the effective radius, and combining the technology with other technologies such as photolithographically etched masks to produce arrays of gradient index lenses. As a result of this ongoing research, the gradient index lens is expected to continue to be the enabling optical technology in the first decade of the new millennium and beyond.