Microwave amplification with nanomechanical resonators

TL;DR

This paper demonstrates a new microwave amplification method using a nanomechanical resonator, achieving significant gain with potential for quantum-limited noise performance, offering a simpler alternative to superconducting devices.

Contribution

Introduces a mechanical resonator-based microwave amplifier that simplifies design and approaches quantum-limited noise performance, expanding options for sensitive electrical measurements.

Findings

Achieved 25 dB signal amplification.

Measured 20 quanta of added noise.

Demonstrated coherent stimulated emission in a mechanical system.

Abstract

Sensitive measurement of electrical signals is at the heart of modern science and technology. According to quantum mechanics, any detector or amplifier is required to add a certain amount of noise to the signal, equaling at best the energy of quantum fluctuations. The quantum limit of added noise has nearly been reached with superconducting devices which take advantage of nonlinearities in Josephson junctions. Here, we introduce a new paradigm of amplification of microwave signals with the help of a mechanical oscillator. By relying on the radiation pressure force on a nanomechanical resonator, we provide an experimental demonstration and an analytical description of how the injection of microwaves induces coherent stimulated emission and signal amplification. This scheme, based on two linear oscillators, has the advantage of being conceptually and practically simpler than the Josephson junction devices, and, at the same time, has a high potential to reach quantum limited operation. With a measured signal amplification of 25 decibels and the addition of 20 quanta of noise, we anticipate near quantum-limited mechanical microwave amplification is feasible in various applications involving integrated electrical circuits.