Label-free neurophotonics: electro-plasmonic biosensors for ultrasensitive detection of electrogenic activity of cells (Conference Presentation)

Harnessing the unprecedented spatiotemporal resolution capability of light to detect electrophysiological signals has been the goal of scientists for nearly 50 years. Advancements in this field could open new frontiers in neuroscience, cardiology and cellular biology. Yet, progress towards that goal remains elusive due to lack of electro-optic translators that can efficiently convert electrical activity to high photon-count optical signals. Here, we introduce an ultrasensitive and extremely bright nanoscale electric-field probe. Our electro-active plasmonic nanoantenna, offering ~3.25x10^3 times enhanced electric-field sensitivities than conventional plasmonic nanoantennas, overcomes the low sensitivity and photon-count limitations, and enables us to realize optical detection of electric-field dynamics with signal-to-shot-noise ratios (SSNR~ 60-220) from diffraction limited spots. We demonstrate label-free optical recording of field dynamics with sub-millisecond temporal resolution.