[Up-conversion luminescence and volumetric display research on Er(0.5): FOG material excited by 1 520 nm laser].

The volumetric display technology is one of the important science frontiers of modern society. Multi-photon up-conversion volumetric 3-D display, attractive especially in its self-spatial vision, has the advantages of total-solidification, high reliability and speedy operation so that it has a broad range of applications. The up-conversion luminescence of oxyfluoride glass material Er(0.5): FOG, when excited by 1 520 nm semiconductor laser, was studied. The common-fluorescence spectra were measured also, in order to know up-conversion sufficiently. It was found that there are several up-conversion luminescence lines (407.43, 411.20 nm), (522.51(m), 528.57 nm), (540.53(m), 543.70, 549.00 nm), (654.75(m), 665.50 nm) and 802.10(m) nm, which can be recognized as the fluorescence-transitions of (2G4F2H)9/2 --> 4 I15/2, 4H11/2 --> 4 I15/2, 4S3/2 --> 4 I15/2, 4F9/2 --> 4I15/2 and 4I9/2 --> I15/2 respectively. It is interesting that the slopes of log F-log P curves, the double logarithmic variation of up-conversion luminescence intensity F with the laser power P, are various for these observed up-conversion luminescences, which are valuable for volumetric display. The comprehensive analysis found that the (2G4F2H)9/2 --> 4I15/2 up-conversion luminescence is a four photon up-conversion luminescence, while [2 H11/2 --> 4I15/2, 4S3/2 --> 4I15/2 and 4F9/2 --> 4I15/2] up-conversion luminescence is three-photon up-conversion luminescences, and 4I9/2 --> 4I15/2 up-conversion luminescence is a two-photon up-conversion luminescence. It was found also that the absorption from the ground-state 4I15/2 level to first excited level is very large, resulting in the fact that the sequential energy transfer and step-by-step absorption up-conversion are readily to happen.