Confinement and manipulation of photons using microcavities have triggered intense research interest in both basic and applied physics for more than a decade. Prominent examples are whispering gallery microcavities which confine photons by means of continuous total internal reflection along a curved and smooth surface. The long photon lifetime, strong field confinement, and in-plane emission characteristics make them promising candidates for enhancing light-matter interactions on a chip. In this book, we will introduce different ultra-high-Q whispering gallery microcavities, and focus on their applications in enhancing light-matter interaction, such as ultralow-threshold microlasing, highly sensitive optical biosensing, nonlinear optics, cavity quantum electrodynamics and cavity optomechanics.

Confinement and manipulation of photons using microcavities have triggered intense research interest in both basic and applied physics for more than a decade. Prominent examples are whispering gallery microcavities which confine photons by means of continuous total internal reflection along a curved and smooth surface. The long photon lifetime, strong field confinement, and in-plane emission characteristics make them promising candidates for enhancing light-matter interactions on a chip. In this book, we will introduce different ultra-high-Q whispering gallery microcavities, and focus on their applications in enhancing light-matter interaction, such as ultralow-threshold microlasing, highly sensitive optical biosensing, nonlinear optics, cavity quantum electrodynamics and cavity optomechanics.