We explore new concepts for electro-optic (EO) modulator designs based on local-field enhancement and electrodes in close proximity for improving the performance of nonlinear materials. Using nanopatterned metals or conductive materials for electrodes and plasmonic elements we show that the effective nonlinearity can be enhanced and concurrently the driving voltage reduced for electro-optic active materials. We especially devote our attention on EO modulator applications using polymers doped with active chromophores. Our substrate materials are mesoscopically patterned using focused ion beam milling. The critical dimensions of the features are smaller than a wavelength. The effective medium theory is used to analyze the results.
Mach-Zehnder interferometers have been the primary type of architecture for construction of polymeric electro-optic modulators. Recent attention has been given to electro-optic modulators in the reflection geometry as well as modulators that employ a resonant cavity to enhance activity or provide for modulator compactness. Most efforts have focused on the Attenuated Total Refelction (ATR) modulators which utilize a guided surface plasmon mode for providing sharply defined angles of incidence at which intesity modulation can be efficiently achieved. This is also the basis of many sensign devices where in both modulation and sensing an active region is placed adjacent to the metal guide. In this work we focus on alternative optical scheems to the ATR for modulation and sensing as well as the possibility of enhanced ATR activity. Resonant cavities are formed using photonic crystals or leaky wave structures which offer the possibiilty of efficient modulation and sensing.