A millimeter-wave near-field scanning probe with an optical distance control

We describe the design of a near-field millimeter (mm) wave resistivity microscope with a resonant-slit probe with a special emphasis (i) on the probe fabrication and (ii) on the probe–sample separation control. We describe an optical and capacitive control of the probe–sample separation. We study dependence of the millimeter-wave reflectivity of different materials on the probe–sample distance.