Photonic band and whispering gallery mode emitters

Semiconductor microcavities have potentialities of ultra-small laser suitable for large scale integration and thresholdless operation under the single mode condition that only one cavity mode is allowed in the electron transition spectrum. They are categorized into VCSELs, photonic band crystals and whispering gallery mode cavities. Utilizing a high refractive index contrast between semiconductor and air, the latter two can realize a high-Q resonance and ultimate strong optical confinement, which are required for the single mode condition.