Micromachined Optical Near-Field Bow-Tie Antenna Probe with Integrated Electrostatic Actuator

A bow-tie antenna structure consisting of two opposing metal electrodes separated by a narrow gap is fabricated with an integrated electrostatic actuator to allow the gap to be narrowed further. This configuration allows the near-field localization and conversion efficiency to be optimized beyond that achievable by direct fabrication. The structure is expected to represent an excellent near-field source for high-resolution imaging with high optical transmittance. Electrostatic actuation is demonstrated in both contact- and noncontact-mode operations, and near-field imaging is successfully performed using the device in the illumination mode.