Dynamical electrical tuning of a silicon microsphere: used for spectral mapping of the optical resonances

In this work, electrical square pulses at various duty cycles are applied to a silicon microsphere resonator in order to continuously tune the refractive index of a silicon microsphere and to map the optical resonance in the time domain. A continuous-wave semiconductor diode laser operating in the L-band is used for the excitation of the silicon microsphere optical resonances. The 90° transverse magnetically polarized elastic scattering signal is used to monitor the silicon microsphere resonances. We show that at a constant input laser wavelength, up to five high-quality-factor optical resonances can be scanned by dynamical electrical tuning of the silicon microsphere cavity.