White upconversion luminescence generation from Ho3+ singly doped chalcohalide glasses

Bright white light which compose of blue, green and red emission bands from Ho3+ single doped Ge–Ga–S–CsCl (CsBr) chalcohalide glasses under 900 nm infrared laser excitation were observed and investigated. The calculated color coordinates proved that the light were close to the natural sunlight. The low phonon energy of the local surrounding of Ho3+ ions and short ultra-violet cut-off edge resulted in the strong blue emission, as well as the enhanced green and red upconversion luminescence. It was also found that color coordinates of these white lights were independent on the excitation intensity. The result indicated that Ho3+ ions singly doped chalcohalide glass can be promising candidate for white light source, 3-dimensional display or color tunable visible laser.