SCHOTT solutions no. 1/2009 > Forschung und Entwicklung

The next laser glass generations should be able to stand up to the higher stress of improved high peak power lasers. Photo: Lawrence Livermore National Laboratory

Journey to the Future
of Glass

What advances are likely to come along with glass and similar materials over the next 20 years ? Former recipients of the Otto Schott Research Award gave exciting answers to this question.

Thilo Horvatitsch

Such immense scientific expertise on glass hardly ever gets together, like it did at the corporate headquarters of SCHOTT in Mainz when the 10th Otto Schott Research Award was presented in November of 2008. Twelve former award winners met for the first time ever at this event and turned this anniversary celebration into a journey to the future of their respective fields. A future that is also based on quite a long past. After all, glass is a material that mankind has known for thousands of years. In the meantime, this transparent material with a multitude of different properties has even conquered high-tech applications, such as lithography of microchip structures, for instance.

However, those who feel that the gold digger times are over with will be quite surprised. In many respects, glass is still virgin soil and holds plenty of potential for surprises in the future. This could be seen during the high profile presentations that were held at the two-day symposium to mark the tenth award ceremony. The researchers were asked to develop futuristic technological scenarios and roadmaps leading up to the year 2025 that were integrated into three clusters: “Optics and Photonic Applications”, “Structures and Properties of Glassy Materials”, as well as “Chemical and Thermal Applications”.
Thanks to their microstructures, photonic crystal fibers – shown here in a strong­ly magnified cross section – offer excellent optical properties and open up many new areas of application. Photo: Fraunhofer IOF

Tomorrow’s super glass

In terms of the traditional role that the glass of the future will play, the main objective is to continue its development with respect to higher stability, break resistance, thermal resistance and transparency – characteristics that will allow it to meet the higher material demands of photovoltaic solar modules or architecture even better.

The “career” that glass has had as a unique functional material is even more incredible. Qualities like excellent surface structurability, special dielectric properties for Micro-Electro-Mechanical Systems (MEMS), or optical functions, such as prevention of light reflections based on the example of the eye of a moth, are being sought. But glass is also interesting as an active optical material. Here, glass topped the list as a laser active medium for researchers: Dr. John Campbell from Lawrence Livermore National Laboratory (LLNL) in California explained that all of today’s high peak power (HPP) laser systems use special laser glasses. For instance, the light from the 1.8 megajoule laser at the LLNL is the result of a series of neodymium-doped phosphate glasses and radiates onto an extremely small target filled with heavy hydrogen. Inside this, a laser pulse can ignite fusion plasma that is many millions of degrees in temperature in only a few billionths of a second. The next generations are now focusing on advanced glasses, as well as polycrystalline ceramics, that stand up to thermal and optical stress through improved HPP lasers. After all, these are expected to perform at a frequency of ten hertz in the megajoule range and be ready for use more than just a couple times a day. This is also a topic for development at SCHOTT, as a supplier of laser glasses, an LLNL partner already for decades.

Professor Andreas Tünnermann from the Friedrich Schiller University in Jena spoke on photonic crystal fibers with significantly improved optical properties for use in modern high performance fiber lasers, for instance. Unlike traditional optical fibers, their properties are not based on basic materials that have been doped differently, but rather on the unique microstructure of the fibers, whose surrounding coating is filled with tiny canals in the longitudinal direction. This not only makes the further development of fiber lasers possible, photonic crystal fibers also open up many other fields of application: for instance, with gas-filled channels, they can be used as sensors or frequency multipliers in telecommunications.

Professor Hideo Hosono from Tokyo Institute of  Technology looked beyond the rim of his glass teacup to other non-crystalline materials. His transparent amorphous oxide semiconductors (TAOS) made of indium gallium zinc oxide should make it possible to manufacture thin-film transistors (TFT) more cost-effectively. The flexible and transparent electronic components are suited for use in transparent displays, such as car windshields, for instance, and promise higher transistor densities and quicker switching rates than comparable modules based on conventional transparent semiconductors.
Many former award winners also took part in the presentation of the 10th Otto Schott Research Award (from left to right): Front row: Prof. Don Uhlmann (Trustee Ernst Abbe Fund), Prof. Himanshu Jain, Dr. Hans-Joachim Konz (SCHOTT Board member), Prof. Akio Ikesue (Award winner 2008), Prof. Walter Kob, Prof. Gerd Müller (Trustee Ernst Abbe Fund). Middle row: Dr. Dieter Fuchs, Dr. Natalia Veshcheva, Phd. David Griscom, Prof. Jianrong Qiu, Prof. Prabhat Gupta. Back row: Prof. Reinhard Conradt, Prof. Andreas Tünnermann, Dr. John Campbell, Anne-Jans Faber. Photo: SCHOTT/A. Sell

Broader knowledge base

Creating materials with new functionalities requires a deeper understanding of the relationship between the composition of glassy materials and their (atomic) structure, in addition to remaining open for new materials. Here, Dr. Natalia Vedishcheva from the Institute of Silicate Chemistry in St. Petersburg, Russia, and Professor Reinhard Conradt from the RWTH in Aachen, Germany, are taking a route that appears to be very promising with their approaches to gaining an understanding of the chemical structure of glass, as is Professor Walter Kob from the University of Montpellier in France with computer simulation of glasses.

Mathematical simulation models also offer the chance to understand, improve and further develop melting processes. Anne-Jans Faber from TNO Science & Industry in Eindhoven, The Netherlands, for instance, showed ways to model the tank design, perform characterization of the glass melting quality and use sensors to perform measurements. Furthermore, ways to reuse the heat that results from the manufacturing process to create energy were also discussed – an important topic for the future as an ecological challenge, as well.

At the end of the two concentrated event days, Dr. Hans-Joachim Konz, a member of the Board of Management at SCHOTT who accompanied the symposium as a moderator, reached a very positive conclusion: “I truly hope that this fruitful exchange between external researchers and those who work for SCHOTT can be continued,” added the Chairman of the Board of Trustees of the Ernst Abbe Fund that helped to finance the conference. <|
Highly distinguished glass researchers met at the German headquarters of SCHOTT in Mainz to attend the 10th presentation of the Otto Schott Research Award. The accompanying symposium featured outstanding expert presentations – and offered an optimistic outlook on the glasses and materials of the future. Photos: SCHOTT/A. Sell