Passive Cooling of a Micromechanical Oscillator with a Resonant Electric Circuit

TL;DR

This paper demonstrates a method to passively cool a micromechanical oscillator using a resonant electric circuit, achieving significant temperature reduction and offering a potentially simpler alternative to optical cooling at low temperatures.

Contribution

The authors introduce a capacitively coupled rf resonant circuit technique for passive cooling of micromechanical oscillators, showing effective cooling from room temperature to cryogenic levels.

Findings

Cooling of a 7 kHz cantilever from room temperature to 45 K

Agreement between experimental results and theoretical model

Potential for ground state cooling in cryogenic systems

Abstract

We cool the fundamental mode of a miniature cantilever by capacitively coupling it to a driven rf resonant circuit. Cooling results from the rf capacitive force, which is phase shifted relative to the cantilever motion. We demonstrate the technique by cooling a 7 kHz cantilever from room temperature to 45 K, obtaining reasonable agreement with a model for the cooling, damping, and frequency shift. Extending the method to higher frequencies in a cryogenic system could enable ground state cooling and may prove simpler than related optical experiments in a low temperature apparatus.