| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1493655 | Optical Materials | 2015 | 6 Pages |
•The 4I9/2–4I13/2 emission band of Er3+ is potentially interesting for CH4 detection.•Substituting S by O or Se does not spectrally shift this band but rather weakens it.•The intensity of the 4I9/2–4I13/2 band varies significantly in powdered and bulk materials.•Radiation diffusion explains this effect and is confirmed by Monte-Carlo simulations.
The 4I9/2–4I13/2 emission band of Er3+ is potentially interesting for CH4 detection because it can overlap with the optical absorption band of CH4. GaLaS and GeGaS glasses doped with Er3+ ions show the desirable emission under 808 nm excitation. An attempt of spectrally shifting 4I9/2–4I13/2 emission band by substituting S by O or Se to obtain a perfect match to the absorption band of CH4 leads to the weakening and disappearance of the 4I9/2–4I13/2 band. This phenomenon is tentatively related to the acceleration of non-radiative relaxation in the case of oxygen addition and to the suppression of up-conversion in the selenium substitution case. The relative intensity of the 4I9/2–4I13/2 band (with respect to the 4I13/2–4I15/2 band) varies significantly in powdered and bulk materials. This effect is discussed in terms of the radiation diffusion (i.e. radiation trapping) model and is confirmed by Monte-Carlo simulations.
