Preparation and spectral analysis of 4.3%Dy:YCa4O(BO3)(3) and 5%Dy,1.25%Tb:YCa4O(BO3)(3) crystals for potential use in solid state yellow lasers

Dy:YCa4O(BO3)(3) (Dy:YCOB) and Dy,Tb:YCa4O(BO3)(3) (Dy,Tb:YCOB) single crystals with different doping ratios were grown through the Bridgman technique, and the spectroscopic properties of the crystals were investigated. The crystals were designed as a laser gain medium to generate a tunable yellow laser pumped by commercially available similar to 450 nm blue laser diodes (LD). For the 5%Dy,1.25%Tb:YCOB crystal, the segregation coefficients K-eff of Dy3+ and Tb3+ ions were calculated to be 0.924 and 0.871. The phonon energy of the Dy,Tb:YCOB crystal was 935 cm(-1). For the pump source of a 453 nm diode laser, the absorption cross-sections sigma(abs) of 4.3%Dy:YCOB and 5%Dy,1.25%Tb:YCOB were 0.60 x 10(-21) cm(2) and 0.84 x 10(-21) cm(2), respectively. The emission cross-sections sigma(em) of 4.3%Dy:YCOB and 5%Dy,1.25%Tb:YCOB were 2.56 x 10(-21) cm(2) and 5.34 x 10(-21) cm(2), and the FWHMs of 4.3%Dy:YCOB and 5%Dy,1.25%Tb:YCOB were 8.9 nm and 13.4 nm for an emission wavelength of 584 nm. The doping trace amounts of Tb3+ ions will improve the yellow laser output from Dy3+ ions and effectively enhance the emission cross-section of yellow light. The fluorescence lifetimes were fitted to 631 mu s and 802 mu s for the 4.3%Dy:YCOB and 5%Dy,1.25%Tb:YCOB single crystals. These results demonstrate that the 5%Dy,1.25%Tb:YCOB crystal is a potential laser crystal with a high probability to generate a tunable yellow laser.