Modified weak measurements for detecting photonic spin Hall effect

TL;DR

This paper introduces a modified weak measurement technique capable of detecting the photonic spin Hall effect even when probe wavefunctions are distorted, extending applicability beyond traditional weak and strong measurement regimes.

Contribution

The authors develop a modified weak measurement method that remains effective under probe distortion and in intermediate coupling regimes, enhancing detection capabilities for the photonic spin Hall effect.

Findings

Modified weak measurement works in strong, weak, and intermediate regimes.

Experimental results agree with the modified theory's predictions.

The scheme detects spin-dependent splitting when traditional methods fail.

Abstract

Weak measurement is an important technique for detecting the tiny spin-dependent splitting in photonic spin Hall effect. The weak measurement is only valid when the probe wavefunction remains almost undisturbed during the procedure of measurements. However, it does not always satisfy such condition in some practical situations, such as in the strong-coupling regime or the preselected and postselected states are nearly orthogonal. In this paper, we develop a modified weak measurement for detecting photonic spin Hall effect when the probe wavefunction is distorted. We find that the measuring procedure with preselected and postselected ensembles is still effective. This scheme is important for us to detect the photonic spin Hall effect in the case where neither weak nor strong measurements can detect the spin-dependent splitting. The modified theory is valid not only in weak-coupling regime but also in the strong-coupling regime, and especially in the intermediate regime. The theoretical models of conventional weak measurements and modified weak measurements are established and compared. We show that the experimental results coincide well with the predictions of the modified theory.