Spherical silica optical microresonators were doped with erbium ions by ion implantation at energies of 925 keV and 2.05 MeV using a rotating stage. After thermal annealing at 800 °C, light was coupled into the microsphere using a tapered optical fiber. An optical quality factor as high as 1.9x107 was observed at ? = 1450 nm, corresponding to a modal loss of only 0.01 dB/cm. When pumped at 1450 nm, multi-mode lasing around 1570 nm is observed at a threshold between 150 and 250 µW depending on the overlap between mode and Er distribution. This work demonstrates the compatibility of ion implantation and microresonator technology.

Nucl. Instrum. Methods Phys. Res. B
Photonic Materials

Kalkman, J., Polman, A., Kippenberg, T., Vahala, K. J., & Brongersma, M. (2006). Erbium-implanted silica microsphere laser. Nucl. Instrum. Methods Phys. Res., Sect B, 242, 182–185. doi:10.1016/j.nimb.2005.08.160