The condition of equilibrium puts constraints on what types of matter can exist, and on their quantitative characteristics. It has been proposed that strong electromagnetic drive can induce new phases not available as ground states, or quantitatively favor one or more competing ground states under a set of similar equilibrium conditions (temperature, magnetic field, etc.). Accessing such phases with electrical measurements, however, is limited by the short timescales during which electromagnetic drive can be applied, itself limited both by the availability of pulsed laser sources and limits on power dissipation within the sample itself. We have developed a versatile THz spectrometer-on-a-chip technique, allowing us to probe the excitation spectrum of deeply sub-diffraction limit sized samples—including van der Waals heterostructures—in the THz frequency range and on picosecond time scales [1]. Critically, our design features both cryogenic compatibility and fast sample exchange, allowing us to bring this technique to bear on highly tunable, complex heterostructures hosting a wide array of correlation driven electronic ground states.
[1] A. Potts, A. Nayak, AFY et. al., “On-chip time-domain terahertz spectroscopy of superconducting films below the diffraction limit.” arXiv:2302.05434