A metamaterial solid-state terahertz phase modulator

Over the past two decades, terahertz time-domain spectroscopy(1) and quantum-cascade lasers(2) have been two of the most important developments in terahertz science and technology. These technologies may contribute to a multitude of terahertz applications that are currently under investigation globally(3). However, the devices and components necessary to effectively manipulate terahertz radiation require substantial development beyond what has been accomplished to date. Here we demonstrate an electrically controlled planar hybrid metamaterial device that linearly controls the phase of terahertz radiation with constant insertion loss over a narrow frequency band. Alternatively, our device may operate as a broadband terahertz modulator because of the causal relation between the amplitude modulation and phase shifting. We perform terahertz time-domain spectroscopy, in which our hybrid metamaterial modulator replaces a commercial mechanical optical chopper, demonstrating comparable broadband performance and superior high-speed operation.