Lasing properties of Er3+ activated SiO2-HfO2 coated microspheres

Optical microresonators are a very promising component for use in optoelectronics. They have very high quality factors and low mode volumes which makes them suitable for many applications such as lasing, sensing or non-linear optics. We will present our work on microspheres coated with sol-gel Er3+ activated 70SiO(2) - 30HfO(2). In particular the lasing properties of such microspheres will be presented. Different coating thicknesses will be employed and the peak lasing power will be discussed in respect to the coating thickness. The lasing peaks will be identified in respect to the radial and azimuthal numbers of the whispering gallery modes and the assignments will be discussed in terms of mode selectivity.