AVALANCHE UP-CONVERSION IN TM3-DOPED BIGAZYTZR GLASS()

Intense blue fluorescence is observed in a Tm3+-doped BIGaZYTZr fluori de glass after single wavelength red or infrared CW pumping. Dynamics and power dependences of both (1)G(4) and D-1(2) fluorescences under 6 48.7 nm excitation reveal a photon avalanche mechanism in the 3 mol% d oped sample. Selective pursed excitation indicate an almost purely rad iative relaxation at low concentration in agreement with Judd-Ofelt ca lculations. At higher concentration, cross-relaxation energy transfer and excited state absorption mechanism compete to feed the (1)G(4) and D-1(2) levels. The concentration, temperature and time dependences of these fluorescences are investigated.