Quantum Optics Seminar by Sergey Fedorov

Swiss Federal Institute of Technology Lausanne (EPFL)

Nonlinear interferometric position measurements and resonators with enhanced dissipation dilution

The resolution of interferometric position measurements is limited by the laws of quantum mechanics. Commonly understood using linearized models, interferometric position detection is inherently nonlinear due to the cyclicity of the optical phase. This nonlinearity can be a resource or a limitation depending on the task. It is non-negligible when the signal distortion is comparable to the vacuum fluctuations of meter light. Therefore, it has a prominent effect even when the nonlinearity is small if the shot-noise limited resolution of the measurement is high.

In the first part of the talk, I will present the observation and study of interferometric nonlinearity in a membrane-in-the-middle optomechanical cavity in the classical regime, where it manifests as thermal intermodulation noise (TIN) produced by the Brownian motion of a multitude of membrane modes.

In the second part of my talk, I will overview the subject of loss dilution in high-stress mechanical resonators, and present some latest advancements in utilizing this effect for engineering mechanical resonators with low thermal noise. The fractal-like approach to the soft-clamping of fundamental mode will be discussed.