Excited state absorption and laser potential of Mn5+-doped Li3PO4

Crystal field parameters and energy level structure of the MnO43− tetroxo anion in Li3PO4, Ca2PO4Cl and Sr5(PO4)3Cl crystals

“…The 1 E( 1 D)' 3 A 2 spin-forbidden transition gives rise to a sharp line (and related sidebands) in the 8800 cm À1 region, whereas the transitions to the other 1 A 1 , 1 T 1,2 singlet states correspond to weak features superimposed to the main band system. This analysis slightly differs from that reported by Hazenkamp et al [5], who ascribed the low intensity band at about 23,000 cm À1 to the 3 T 1 ( 3 P)' 3 A 2 transition. We think that our assignment, other than supported by the calculations, is also more consistent with the observed band intensities.…”

“…1) we have not observed this dip, however it is clearly visible in the spectrum reported in Ref. [5]. For the rest the present results do not agree with the analysis carried out in Ref.…”

“…These ions usually lie in sites having tetrahedral oxygen coordination either with low (V 3+ , Cr 4+ ) or strong (Mn 5+ , Fe 6+ ) crystal field. In the former case the broadband emission from the 3 T 2 state in the NIR spectral region is attractive for tunable laser application, whereas in the latter the emission from the 1 E level consists mainly of a sharp feature suitable for laser action only in some favourable host lattices [5]. The analysis of the energy level structure of these dopants in suitable hosts is then important in order to assess their prospective applications.…”

“…In this paper we apply this method to the comparative analysis of the low-temperature absorption spectra of the Mn 5+ ion in Li 3 PO 4 , Ca 2 PO 4 Cl and Sr 5 (PO 4 ) 3 Cl crystals. These materials have been extensively investigated in the past by different authors [5,[8][9][10][11][12][13][14], nevertheless there are aspects that still need to be clarified. We have then found it interesting to re-examine their spectral properties using the ECM unified approach and verify how the progressive lowering of the site symmetry affects the structure of the optical bands.…”

Selectively excited luminescence and magnetic circular dichroism ofCr4+-doped YAG and YGG

“…15 The 3 A 2 → 1 E transition in the absorption spectrum of the Cr 4ϩ :YAG system has variously been assigned as the first weak doublet ͑ϳ7800 cm Ϫ1 ͒, 16 the second strong doublet ͑ϳ9000 cm Ϫ1 ͒, 5 or to a pair of weak transitions between these ͑ϳ8265 cm Ϫ1 ͒. 6 In this study, we will show that these assignments are incorrect.…”