Waveguide-Mode-Enhanced Millimeter-Wave Photomodulators

The modulation of millimeter-wave transmission through a silicon wafer upon photoexcitation is typically very inefficient for off-the-shelf low effective charge carrier lifetime wafers, requiring tens kilowatts photoexciting intensity to generate significant modulation. Here we demonstrate that increasing the light-matter interaction millimeter waves using diffractively coupled waveguide modes leads an increase in photomodulation efficiency greater than two orders magnitude, while maintaining switching speed, order $10\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}\mathrm{s}$, bare wafer.