Observation of whispering-gallery modes in Si microdisks at room temperature

Whispering-gallery modes are observed at room temperature in silicon microdisk resonators fabricated on silicon-on-insulator substrates. Sharp luminescent peaks originating from the crystalline silicon film, corresponding to the whispering-gallery modes, are observed to change in microdisks with different diameters. Over 30 times enhancement of the photoluminescence from bulk silicon is observed due to the microdisk.