An optical structure is formed on a surface of the optically resonant system to modify a characteristic of the emitted resonant signal. The optical structure may be configured to impart a phase-shift on a portion of the resonant signal. Because the resonant signal consists of a single resonant mode with an axially symmetric radiation pattern, a phase-shift can be used to, for example, collimate, disperse, direct, and generally shape output characteristics of the emitted resonant signal. The optical structure can also be used to tune the quality factor (Q) of the optically resonant system.