Southwest Quantum Information and Technology

Comparison of the quantum Cramer-Rao bounds for quantum-enhanced resonant detection based on phase and transmission estimation

Presenting Author: Timothy Woodworth, University of Oklahoma
Contributing Author(s): Mohammadjavad Dowran, Ashok Kumar, Alberto M. Marino

The goals of quantum metrology include finding optimal states to probe a system and optimal measurements of those states to obtain as much information as possible about the parameter of interest. Here we study ultimate sensitivity bounds for resonant based detectors, such as plasmonic sensors and optical resonators, when probed with entangled twin beams of light. Resonant detectors experience a resonance shift due to local changes in their environment. This causes both a change in the amplitude and phase of the probing light. We have previously shown experimentally that is possible to use twin beams to obtain a quantum-based enhancement of the sensitivity of a plasmonic sensor when using the change in amplitude to estimate a local change in index of refraction. We now show how further enhancements can be obtained when using the change in phase to estimate the local change in refractive index. We compare ultimate bounds by calculating the quantum Cram\'er-Rao bound for both approaches when using bright twin beams and show experimental schemes that saturate these bounds.

(Session 5 : Saturday from 5:00pm - 7:00pm)