Octave-spanning broad luminescence of Cr3+, Cr4+-codoped Mg2SiO4 phosphor for ultra-wideband near-infrared LEDs

We synthesized Cr3+, Cr4+-codoped Mg2SiO4 phosphors and studied their optical properties for application as a novel wideband near-infrared (NIR) light-source. The phosphors have an ultra-wideband NIR luminescence spectrum of 650-1400 nm. The origin should be the 4 T 2 → 4 A 2 transition of Cr3+ and the 3 T 2 → 3 A 2 transition of Cr4+. The luminescence spectrum spans over one octave range and covers the "optical window in biological tissues". We successfully achieved an ultra-wideband luminescence of 650-1400 nm with a maximum output power of 367.5 W by combining a blue LED with Cr3+ and Cr4+-codoped Mg2SiO4 phosphors in a single package.