Waveguide-Mode-Enhanced Millimeter-Wave Photomodulators

Abstract

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, typically requiring tens of kilowatts of photoexciting intensity to generate significant modulation. Here we demonstrate that increasing the light-matter interaction for the millimeter waves using diffractively coupled waveguide modes leads to an increase in photomodulation efficiency of greater than two orders of magnitude, while maintaining the switching speed, of the order of $10\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}\mathrm{s}$, of the bare wafer.