We developed a persistent phosphor of Y₃Al₂Ga₃O₁₂ doped with Nd³⁺, Ce³⁺, Cr³⁺ ions (YAGG:Nd-Ce-Cr) exhibiting long (>10 h) persistent luminescence at multi-wavelengths of around 880, 1064, and 1335 nm due to f-f transitions of Nd³⁺ and at 505 nm due to Ce³⁺:5d₁→4f transition. The intense near-infrared (NIR) persistent luminescence bands from Nd³⁺ match well with the first (650–950 nm) and second (1000–1400 nm) bio-imaging windows. The NIR persistent radiance of the YAGG:Nd-Ce-Cr phosphor (0.33 × 10⁻¹ mW/Sr/m²) at 60 min after ceasing blue light illumination was over 2 times higher than that of the widely used ZnGa₂O₄:Cr³⁺ red persistent phosphor (0.15 × 10⁻¹ mW/Sr/m²).

By utilizing efficient persistent energy transfer from Ce ³⁺ to Er ³⁺ , we have successfully developed a novel garnet persistent phosphor of Y ₃ Al ₂ Ga ₃ O ₁₂ doped with Er ³⁺ , Ce ³⁺ , Cr ³⁺ ions (YAG G :Er–Ce–Cr) exhibiting long (>10 h) near-infrared (NIR) persistent luminescence (PersL) in the broad range from 1450 nm to 1670 nm due to the typical Er ³⁺ : ⁴ I _13/2 → ⁴ I _15/2 transition in garnet.