Glass - Back to the Future!

Presenting Author:
Nagia Tagiara

article posted 13 July 2016

Ms. Nagia S. Tagiara I received my diploma in Physics from the University of Athens in 2010 and my MSc in Microsystems and Nanodevices from the National Technical University of Athens in 2013. Since 2014 I am working on my PhD thesis at the National Hellenic Research Foundation (NHRF) in Athens, Greece.

TeO2 and zinc-tellurite glasses: properties, structure and second harmonic generation by electro-thermal poling

N.S. Tagiara1,*, D. Palles1, E.D. Simandiras1, A. Kyritsis2, and E.I. Kamitsos1
1Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 116 35 Athens, Greece
2National Technical University of Athens, Zografou Campus, 157 80 Athens, Greece

Tellurite glasses attract special interest because of their relatively low melting temperatures, high refractive index and third-order non-linear susceptibility, due mainly to their lone electron pair on Te.1 In this work we present a study of glasses spanning a wide range of compositions i n the system xZnO-(1-x)TeO2 (0≤x≤0.50). Glasses were prepared by quenching melts of appropriate stoichiometry, and were subsequently characterized by Differential Scanning Calorimetry to determine glass transition temperature (Tg) and by Archimede’s method to measure density (Σ). Glass modification by ZnO was found to increase Tg (Fig. 1) and decrease Σ. The synthesized glasses were studied also by Raman spectroscopy to probe the evolution of tellurite structure upon doping with ZnO (Fig. 2).

Figure 1: Dependence of glass transition temperature Tg on ZnO content (mol%).

Figure 2: Reduced Raman spectra of binary glasses xZnO-(1-x)TeO2.

Homogeneous glasses do not exhibit even-order optical response like second harmonic generation (SHG) because of their centro-symmetric nature. However, post-synthesis treatments like electro-thermal poling may transform optically passive glasses into functional glasses with non-linear optical response. Fig. 3 shows the SHG response of a tellurite glass from the Na2O-ZnO-TeO2 system after thermal poling and demonstrates the development of second-order non-linear properties. The structural changes induced by poling were monitored by infrared spectroscopy and correlated with the SHG efficiency of the poled glasses.

Figure 3: SHG transmission measurements on an electro-thermally poled tellurite glass.

[1] R. A. H. El-Mallawany, in Tellurite Glasses Handbook, Physical Properties and Data (CRC Press LLC, Boca Raton, Florida, 2002).

Support of this work by the General Secretariat for Research and Technology (Greece) is gratefully acknowledged (POLYNANO–KRIPIS project, ΟΠΣ:447963).