Optical spectroscopy and population behavior between ^4I_11/2 and ^4I_13/2 levels of erbium doped germanate glass

In this paper, mid-infrared emission properties and energy transfer mechanism were investigated in Er3+ doped germanate glass pumped by 980 nm diode laser. Spontaneous radiative transition probability and emission cross section at 2.7 aem were calculated to be as high as 36.45 s(-1) and 1.61 x 10(-20) cm(2), respectively. Corresponding upconversion emission spectra and radiative lifetimes of I-4(13/2) level were determined to elucidate the mid-infrared luminescent characteristics. Moreover, population behaviors of Er3+: I-4(11/2) and I-4(13/2) level were analyzed numerically via Inokuti-Hirayama model, rate equations and Dexter's theory. In addition, DSC curves of developed samples were measured and thermal stabilities were studied to evaluate the ability of resisting thermal damage and crystallization. The results indicate that erbium activated germanate glass is a promising candidate for mid-infrared applications. This work may provide beneficial guide for investigation of population behaviors of Er3+ ions at 2.7 mu m emissions.