The 1.2 and 2.0 μm Emission from Ho³⁺ in Glass Ceramics Containing BaF₂ Nanocrystals

Abstract

Ho31 and/or Yb31 doped glass ceramics containing spherical BaF2 nanocrystals sized 10–20 nm were prepared by melt quenching and subsequent thermal treatment. Radiative properties such as transition probabilities (A), radiative lifetimes (τ), branching ratios (β) along with absorption and emission cross sections have been calculated from the absorption spectra. Upon 637 nm excitation, Ho31‐doped glass ceramics yield an intense infrared emission at 1191 nm with a full‐width at half‐maximum of 80 nm and weaker emissions at 980 and 1473 nm. Efficient 1.2 and 2.0 μm infrared emissions have been achieved in Ho31/Yb31 co‐doped glass ceramics under 980 nm excitation, demonstrating the occurrence of energy transfer (ET) from Yb31 to Ho31. The microscopic parameters of the ET processes between Yb31 and Ho31 have been evaluated, revealing that the forward ET Yb31 → Ho31 is more efficient than the backward one and both the processes are mainly assisted by one‐phonon emission (annihilation).

2 μm emission properties and nonresonant energy transfer of Er3+ and Ho3+ codoped silicate glasses

“…9(b). The emission cross section with the participation of m phonons can be determined by following equation39:…”

“…where σ em is the emission cross section of Er 3+ : 4 I 11/2 → 4 I 15/2 , 4 I 13/2 → 4 I 15/2 transitions, which is equal to the one with zero-phonon calculated by the Mc-Cumber equation39 and S 0 is the Huang-Rhys factor, which is 0.31 for rare earth ions38. Such as the above, hν max is the maximum phonon energy of host and k is Boltzmann constant.…”

Natural discharge after pulse and cooperative electrodes to enhance droplet velocity in digital microfluidics

“…The detailed calculation process can be seen elsewhere. 14 The relevant parameters and results are listed in Table I.…”

Quantum‐dots‐precipitated rare‐earth‐doped glass for ultra‐broadband mid‐infrared emissions

“…At present, the MIR emission, especially the emission at 2 μm can be realized from the Tm 3+ : 3 F 4 → 3 H 6 and Ho 3+ : 5 I 7 → 5 I 8 transitions. To enhance their luminescent intensities or to realize the broadband luminescence, the common approach is adding RE sensitizers (eg, Yb 3+ , Nd 3+ , and Er 3+ ) to provide greater absorption efficiency or suitable pumping wavelength for the activated ions . For example, it is possible to introduce the Er 3+ /Tm 3+ , Tm 3+ /Ho 3+ , and Er 3+ /Yb 3+ /Tm 3+ codoped systems to achieve enhanced or tunable luminescence at the near‐ and mid‐infrared range .…”