LAUSR

Highly crystalline and smooth 1% Ho3+ doped ZnO microspheres with diameters ranging from 0.5 to 15 μm were synthesized using laser ablation technique. Near band edge whispering gallery mode (WGM) resonances from Ho:ZnO microspheres with a single oscillation route in the UV range are observed with 355 nm excitation. Apart from the significantly enhanced visible WGM resonances associated with intrinsic oxygen vacancy defects by Ho3+ doping, the visible range WGM resonances associated with the Ho3+ 5F5 → 5I8 emission at 629–690 nm are also observed with a 488 nm excitation. The WGMs of Ho3+ f-f emission possess lower threshold and high Q-factor values.Highly crystalline and smooth 1% Ho3+ doped ZnO microspheres with diameters ranging from 0.5 to 15 μm were synthesized using laser ablation technique. Near band edge whispering gallery mode (WGM) resonances from Ho:ZnO microspheres with a single oscillation route in the UV range are observed with 355 nm excitation. Apart from the significantly enhanced visible WGM resonances associated with intrinsic oxygen vacancy defects by Ho3+ doping, the visible range WGM resonances associated with the Ho3+ 5F5 → 5I8 emission at 629–690 nm are also observed with a 488 nm excitation. The WGMs of Ho3+ f-f emission possess lower threshold and high Q-factor values.