Electro-optic measurement system with high spatial resolution utilizing poled polymer film as external probe tip

A new external electro-optic probing technology has been first demonstrated using a poling electro-optic (EO) polymer film, spin-coated on 20 nm thick grounding perspective aluminum layer which sputtered on a piece of ITO glass (1000μm×1000μm×80μm) as a probe tip, the aluminum layer which has 30% reflectance ratio is also a reference coating. A 1μm interdigital electrode was measured, and the spatial resolution of less than 0.5μm was obtained. Voltage sensitivity was approximately 2mV/Hz. The probing beam reflected from the metal line is phase-modulated by the signal electric field in the EO polymer film, and then converted to amplitude modulation by interference with the reference beam reflected from the 30% reflective coating. The reference electrode makes sure that the most signal voltage drops down in the EO polymer film.