Room temperature photon avalanche upconversion in Ho³⁺doped fluoroindate glasses under excitation at 749 nm

Up-conversion and photon avalanche in oxy-fluoride nano-structured glasses doped with Ho3+

“…When the excitation power increased, the slope between the emission intensity and the pump power changed from 2.06, 2.41 to 1.67, while the rise time decreased after reaching a maximum value (5.75 ms). These characteristic features of the photon avalanche were consistent with those reported in various Ho 3+ -doped materials [9][10][11][12].…”

“…The emission spectra shown in Fig. 4 are consistent with those reported [9][10][11][12]. However, the rise curve of green emission recorded from the nanostructured glass with 0.5 mol% HoF 3 showed the typical temporal evolution behavior corresponding to the photon avalanche up-conversion process.…”

“…They are typical peaks representing the cubic fluoride crystals of b-PbF 2 . This is consistent with the results reported in the previous works [11,16]. Using the Scherrer formula [17], the average crystal size was estimated to be 12-17 nm in diameter.…”

“…In addition, photon avalanche up-conversion is one of the most efficient up-conversion processes [8]. Photon avalanche up-conversion in Ho 3+ was also studied in several crystals [9,10] and glasses [11,12] by pumping with 750 nm light source.…”

“…pump source is weak [9][10][11][12]. However, the excitation wavelength is resonant with the excited-state absorption of the ( 5 I 7 !…”