Sequential three-photon near-infrared quantum cutting in transparent fluorogermanate glass-ceramics containing LaF_3:Tm^3+ nanocrystals

Spectroscopic and structural characterization of transparent fluorogermanate glass ceramics with LaF3:Tm3+ nanocrystals for optical amplifications

“…As for the luminescence mechanism upon 468 nm excitation, three-step sequential three-photon NIR quantum cutting has previously been confirmed by static and dynamic photoemission and excitation spectroscopy [16]. In this respect, Tm 3+ ions in the 1 G 4 state initially generate luminescence at 650 and 1190 nm by radiative decays to 3 F 4 and 3 H 4 levels.…”

“…This could be associated with the relatively low phonon energy (875 cm À1 ) of the fluorogermanate glass assigned to the non-bridging oxygen (NBO) atom vibrations in Q 3 units [32]. Moreover, our previous work has shown the gradual decrease of the maximum phonon energy with the prolongation of soaking time owing to the precipitation of LaF 3 nanocrystals [16]. The significant enhancement of emission intensity in the 410-565 nm range achieved in GC0.05Eu could be ascribed to the decrease of multiphonon relaxation rate benefited from partial incorporation of Eu 3+ ions into LaF 3 nanocrystals with quite low phonon energy ($380 cm À1 [33]).…”

“…Until now, the reported glassy matrix for Tm 3+ emission at 1.2 lm is limited to low-phonon-energy systems (e.g., tellurite [12] and chalcohalide [13]). As a promising host, transparent oxyfluoride glass ceramic has aroused an extensive interest in the optoelectronic field for its combined advantages of optical properties provided by fluoride nanocrystals and the excellent chemical and mechanical stability inherited from the precursor glass [9,[14][15][16][17].…”

REVO4‐Based Nanomaterials (RE = Y, La, Gd, and Lu) as Hosts for Yb3+/Ho3+, Yb3+/Er3+, and Yb3+/Tm3+ Ions: Structural and Up‐Conversion Luminescence Studies

“…The 1 G 4 → 3 H 6 and 1 G 4 → 3 F 4 transitions are connected with the change of spin. However, the long luminescence lifetime of 3 H 4 → 3 H 6 (Δ S = 0) can only be explained by preceding spin‐forbidden transition 1 G 4 → 3 H 4 which, indeed, occurs in the infrared region (1190 nm) …”

Er3+ Ions‐Doped Germano‐Gallate Oxyfluoride Glass‐Ceramics Containing BaF2 Nanocrystals

“…Until present, reports on the Pb/Cd free germanate oxyfluoride glass‐ceramics were still lacking. Zhang et al . prepared Tm 3+ /Yb 3+ co‐doped LaF 3 nanocrystals in 50GeO 2 –20Al 2 O 3 –15LaF 3 –15LiF system and efficient three‐step sequential three‐photon near‐infrared quantum cutting has been demonstrated.…”