doi.org/10.1103/physreva.70.033803
Phys. Rev. A
Photonic Materials

Min, B., Kippenberg, T., Yang, L., Vahala, K. J., Kalkman, J., & Polman, A. (2004). Erbium-implanted high-Q silica toroidal microcavity laser on a silicon chip. Phys. Rev. A, 70(Article number: 33803), 1–12. doi:10.1103/physreva.70.033803