Detecting momentum weak value: Shack-Hartmann versus a weak measurement wavefront sensor

TL;DR

This paper reveals that the Shack-Hartmann wavefront sensor inherently detects the weak value of transverse momentum, bridging classical wavefront sensing with quantum weak measurement concepts, and compares it to dedicated weak measurement sensors.

Contribution

It demonstrates that a common wavefront sensor can measure quantum weak values, extending its application to quantum physics and metrology.

Findings

Shack-Hartmann sensor detects weak values of transverse momentum

Comparison shows higher spatial resolution of weak measurement wavefront sensor

Implications for quantum physics and quantum metrology applications

Abstract

The task of wavefront sensing is to measure the phase of the optical field. Here, we demonstrate that the widely used Shack-Hartmann wavefront sensor detects the weak value of transverse momentum, usually achieved by the method of quantum weak measurement. We extend its input states to partially coherent states and compare it with the weak measurement wavefront sensor, which has a higher spatial resolution but a smaller dynamic range. Since weak values are commonly used in investigating fundamental quantum physics and quantum metrology, our work would find essential applications in these fields.