6533b860fe1ef96bd12c324d

RESEARCH PRODUCT

Subwavelength imaging of field confinement in a waveguide-integrated photonic crystal cavity

subject

description

A photonic crystal microcavity is designed to obtain an original field distribution inside the cavity and the structure is etched inside a silicon-on-insulator waveguide. Spectral location of the photonic band gap and cavity resonance are identified by using transmittance measurements and by analyzing the light collected by a scanning near-field optical microscope probe exactly positioned on the center of the cavity. The results obtained with the two techniques are in very good agreement. Then the near-field distribution above the device is mapped and light confinement inside the cavity is evidenced. Moreover, this confined light presents some remarkable patterns which clearly correspond to the cavity mode field distribution computed by using a plane-wave expansion method and taking into account the probe resolution.