Self-Suspended Microdisk Lasers with Mode Selectivity by Manipulating the Spatial Symmetry of Whispering Gallery Modes

Miniature semiconductor lasers have attracted a large amount of interest owing to their potential as highly integrated components in photonic circuits or in sensors. Particularly, microdisk lasers exploiting whispering gallery modes have been regarded as important candidates because of their relatively small footprint and low threshold. However, it has been challenging for microdisks to operate under single mode operation and to lase in a preselected mode. We report subwavelength microdisk resonators suspended in air with connecting bridges and propose a simple method using the number and symmetry of bridges to enhance or reduce wave confinement in the whispering gallery cavity. Moreover, a suitable choice of bridges increases the quality factor of microdisks compared to microdisk resonators without bridges. Using this method, we demonstrate single mode lasing of preselected modes at telecommunication wavelength