The Multi-channel Emission Transitions Of Sm³⁺ In Heavy Metal Silicate Glasses

Rare-earth doped glasses are important materials for fluorescent display devices, optical detectors, bulk lasers, optical fibers, waveguide lasers and optical amplifier. Among the oxide glasses, heavy-metal-oxide glasses possess high refractive index, good IR transparence, lower phonon energy, which make the rare-earth ions achieve efficient fluorescence in them. Based on this consideration, Sm3+ doped heavy metal silicate glasses have been designed, fabricated and characterized. The followings are results this work achieved:1. Sm3+ doped heavy metal cadmium-aluminum-silicate (CAS) and lithium yttrium aluminum silicate (LYAS) glasses have been fabricated by high temperature melting method. Based on optical absorption, Judd-Ofelt parameters Ω2,Ω4 and Ω6 have been derived to be 2.87×10-20, 3.34×10-20 and 1.86×10-20cm2 in CAS glasses and 4.12×10-20,4.26×10-20 and 2.11×10-20cm2 in LYAS glasses, respectively. Then the radiative transition probabilities, radiative lifetimes and fluorescence branch ratios of Sm3+ in glasses were calculated. The glasses emit bright reddish-origin light under excitation of long-wave UV and blue light. Based on FL formula, the emission cross-section of Sm3+ in visible and IR bands have been derived. Based on IR transmittance spectrum, the maximum-phonon-energy of Sm3+ doped CAS and LYAS glasses have been calculated to be ～980cm-1 and 1019 cm-1.2. Optical radiative parameters for multi-channel visible transition emissions have been determined in Sm3+ doped cadmium-aluminum- silicate (CAS) and lithium yttrium aluminum silicate (LYAS) glasses under the excitation of a violet and blue light emitting diode (LED). For the derivation, the necessary fluorescence spectra were measured and calibrated in an integrating sphere, which was connected to a CCD detector with a 400 μm core optical. The total quantum yield of the visible fluorescence of Sm3+ in CAS glasses has been calculated to be 2.3% and 2.52% under violet and blue LED excitation, respectively. The total quantum yield of the visible fluorescence of Sm3+ in LYAS glasses has been derived to be 11.58% under excitation of blue LED. Investigations on absolute spectral parameters for multi-channel visible transition emissions of Sm3+ in heavy metal silicate glass provide a valuable reference in developing efficient display and illumination devices.The present research indicates that, the heavy-metal-silicate glasses with multi-channel radiative transition emissions expose its potential applications in tunable laser, medical light source and NIR optoelectronic devices.