Developing sub-THz nanoscale quantum sensing for quantum materials (and Devices)

Amir H. Safavi-Naeini, Associate Professor of Applied Physics
Zhi-xun Shen, Paul Pigott Professor of Physical Sciences, Professor of Physics, Professor of Applied Physics, Senior Fellow of the Precourt Institute for Energy

Summary: One of the primary challenges in quantum materials research is understanding quasiparticles and collective excitations, which calls for advanced scanning probe techniques that have direct access to those nanoscale excitations. Microwave Impedance Microscopy (MIM) is such a technique utilizing near-field interaction between microwaves and materials to precisely measure conductivity and permittivity with nanometer resolution¹ . Its non-destructive nature, minimal sample preparation requirements, and adaptability to various experimental conditions, position it as a desirable electrical sensing tool. Yet, the applicability of MIM is currently limited by its frequency range (1 - 20 GHz, hence not sensitive to highly conductive samples), and signal to noise ratios. The limitations leave a knowledge gap for understanding intriguing quantum phenomena, like unconventional superconductivity and topological superconductivity.

The primary goal of this project is to develop a novel squeezed, millimeter-wave scanning microscopy to fill this knowledge gap, via a collaboration between Zhi-Xun Shen (ZXS) and Amir Safavi-Naeini's (ASN) groups. We propose a two-year program where we develop a cryogenic mm-wave resonant scanning system in the first year and in the second year focus on utilizing squeezed vacuum to enhance signal-to-noise ratio in a low power regime.