Third harmonic generation studies of 1.06 μm Nd:YAG laser beam in Li2SO4–MgO–P2O5 glass system-influence of CuO

Abstract

Glasses of the composition Li2SO4–MgO–P2O5:CuO were synthesized. The spectroscopic investigations on these samples revealed that there is a gradual reduction of Cu2+ ions in to Cu + ions (that occupy tetrahedral sites) in the glass matrix as the content of CuO is increased. Infrared spectroscopy studies have clearly demonstrated an increased degree of connectivity between various structural groups of the glass network with increase of CuO concentration. Third harmonic generation (THG) beam intensity of Nd:YAG laser (λ = 1064 nm) probing beam (of the power 0–100 J/m2) induced due to the interaction of inherent dipoles with the incident laser beam, is observed to decrease as the concentration of CuO is increased. The analysis of the results of these studies indicated that Li2SO4–MgO–P2O5 glass samples doped with small content of CuO ~ 0.2 mol% are more favorable for achieving high power THG signal with low absorption due to phonons. Hence, such glasses may be useful for optoelectronic devices. However, the spectroscopic studies indicated that in the samples containing higher content of CuO there is higher fraction of Cu+ ions that occupy network forming (Td) positions; such increased degree of polymerization in the glass matrix appears to be a hindrance for accomplishing higher intensity of THG signal due to large phonon losses. These results were found to be in concurrence with the inferences from other studies that include electrical properties, positron annihilation lifetime (PAL) spectroscopy and mechanical properties.