[Photon avalanche upconversion in Er3+-doped telluride glass excited by 980 nm laser]

By laser excitation at the wavelength of 980 nm, efficient upconversion emission at 550 nm was observed in Er3+ doped telluride glass. The upconversion intensity varies nonlinearly with the excitation power with a threshold of 44 mW. The photon response time, of the order of tens of milliseconds, is much longer than the emission lifetimes. Moreover, the response time decreases with the increase in excitation power. The power dependence of the intensity and response time indicates that the green emission is generated through photon avalanche upconversion. Compared with 690 or 579 nm excitation wavelength, 980 nm is more efficient.