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Science

Observation of the Spin Hall Effect of Light via Weak Measurements

Onur Hosten, Paul G. Kwiat

Published Jan 10, 2008• 2,026 citations
Publisher

Abstract

We have detected a spin-dependent displacement perpendicular to the refractive index gradient for photons passing through an air-glass interface. The effect is the photonic version of the spin Hall effect in electronic systems, indicating the universality of the effect for particles of different nature. Treating the effect as a weak measurement of the spin projection of the photons, we used a preselection and postselection technique on the spin state to enhance the original displacement by nearly four orders of magnitude, attaining sensitivity to displacements of approximately 1 angstrom. The spin Hall effect can be used for manipulating photonic angular momentum states, and the measurement technique holds promise for precision metrology.

DOI
10.1126/science.1152697

Related papers

Spin Hall effect of light via weak measurements: Sharp and smooth index variations

Onur Hosten, Paul G. Kwiat

Using ldquoquantum weak-measurementsrdquo as a coherent enhancement technique for small signals, we have measured the recently proposed ldquospin Hall effectrdquo of light at an air-glass interface, and are working on the smoothly varying refractive-index case.

Conference on Lasers and Electro-Optics•May 4, 2008•0 citations

Optimal preselection and postselection in weak measurements for observing photonic spin Hall effect

Xinxing Zhou, Xing Li, Hailu Luo +1 more

Photonic spin Hall effect (SHE) holds great potential applications in precision metrology. How to obtain a high measurement precision is an important issue to detect the photonic SHE. In this Letter, we propose using optimal preselection and postselection in weak measurements to enhance the measurement precision. We find that the maximum weak value and pointer shift can be obtained with an optimal overlap of preselection and postselection states. These findings offer the possibility for improving the precision of weak measurements and thereby have possible applications for accurately characterizing the parameters of nanostructures.

arXiv:1404.2721•Applied Physics Letters•Feb 3, 2014•50 citations

Modified weak measurements for detecting photonic spin Hall effect

Shizhen Chen, Xinxing Zhou, Chengquan Mi +2 more

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.

arXiv:1505.04239•May 16, 2015•1 citation

Modified weak measurements for the detection of the photonic spin Hall effect

Shizhen Chen, Xinxing Zhou, Chengquan Mi +2 more

Weak measurement is an important technique for the detection of the tiny spin-dependent splitting in photonic spin Hall effect. The weak measurement is only valid when the probe wave function 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 when the preselected and postselected states are nearly orthogonal. In this paper, we develop a modified weak measurement for the detection of the photonic spin Hall effect when the probe wave function 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 the 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.

Physical Review A•Jun 5, 2015•81 citations

Nonlocal nonlinear control of photonic spin Hall effect in strongly interacting Rydberg media

Wenzhang Liu, Muqaddar Abbas, Pei Zhang +1 more

Abstract We present a theoretical study demonstrating that the photonic spin Hall effect (PSHE) can be both actively tuned and greatly amplified by exploiting the nonlocal, nonlinear optical response of a strongly interacting Rydberg gas operating under electromagnetically induced transparency. Rather than relying on fixed phase metasurfaces or conventional Kerr materials, long range interactions between Rydberg atoms create a spatially extended, intensity dependent refractive index profile that enables dynamic spin resolved beam deflection. In a glass–Rydberg–glass trilayer model, we show that the PSHE displacement can be varied smoothly in magnitude and even reversed in sign by adjusting atomic density, probe intensity, laser detunings, and interaction strength. This nonlocal nonlinearity transforms the typically weak PSHE into a macroscopically observable and dynamically controllable effect. Our results establish a versatile platform for reconfigurable spin-dependent photonic control, with potential applications in high-sensitivity optical metrology, spin-based beam steering, and tunable quantum-optical information processing.

arXiv:2506.00540•New Journal of Physics•Nov 1, 2025•0 citations

Amplifying a Tiny Optical Effect

Kevin J. Resch

How do you measure a transverse shift of a light beam to within a nanometer? Recently, physicists predicted (1) that light could experience such a shift similar to what happens to electrical currents in semiconductors through the spin Hall effect (2–4). On page 787 of this issue, Hosten and Kwiat (5) use “weak measurement,” a controversial procedure from the foundations of quantum mechanics, to amplify this spin Hall effect in light (SHEL) rather than detecting it directly. In their experiment, they boost the tiny shift by a factor of 10,000, detecting it for the first time and characterizing it at the angstrom scale. This realizes one of the long-standing promises of weak measurement and demonstrates its potential in precision measurements.

Science•Feb 7, 2008•43 citations
We have detected a spin-dependent displacement perpendicular to the refractive index gradient for photons passing through an air-glass interface. The effect is the photonic version of the spin Hall effect in electronic systems, indicating the universality of the effect for particles of different nature. Treating the effect as a weak measurement of the spin projection of the photons, we used a preselection and postselection technique on the spin state to enhance the original displacement by nearly four orders of magnitude, attaining sensitivity to displacements of approximately 1 angstrom. The spin Hall effect can be used for manipulating photonic angular momentum states, and the measurement technique holds promise for precision metrology.
Photonic spin Hall effect (SHE) holds great potential applications in precision metrology. How to obtain a high measurement precision is an important issue to detect the photonic SHE. In this Letter, we propose using optimal preselection and postselection in weak measurements to enhance the measurement precision. We find that the maximum weak value and pointer shift can be obtained with an optimal overlap of preselection and postselection states. These findings offer the possibility for improving the precision of weak measurements and thereby have possible applications for accurately characterizing the parameters of nanostructures.
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.
Weak measurement is an important technique for the detection of the tiny spin-dependent splitting in photonic spin Hall effect. The weak measurement is only valid when the probe wave function 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 when the preselected and postselected states are nearly orthogonal. In this paper, we develop a modified weak measurement for the detection of the photonic spin Hall effect when the probe wave function 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 the 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.
Abstract We present a theoretical study demonstrating that the photonic spin Hall effect (PSHE) can be both actively tuned and greatly amplified by exploiting the nonlocal, nonlinear optical response of a strongly interacting Rydberg gas operating under electromagnetically induced transparency. Rather than relying on fixed phase metasurfaces or conventional Kerr materials, long range interactions between Rydberg atoms create a spatially extended, intensity dependent refractive index profile that enables dynamic spin resolved beam deflection. In a glass–Rydberg–glass trilayer model, we show that the PSHE displacement can be varied smoothly in magnitude and even reversed in sign by adjusting atomic density, probe intensity, laser detunings, and interaction strength. This nonlocal nonlinearity transforms the typically weak PSHE into a macroscopically observable and dynamically controllable effect. Our results establish a versatile platform for reconfigurable spin-dependent photonic control, with potential applications in high-sensitivity optical metrology, spin-based beam steering, and tunable quantum-optical information processing.
How do you measure a transverse shift of a light beam to within a nanometer? Recently, physicists predicted (1) that light could experience such a shift similar to what happens to electrical currents in semiconductors through the spin Hall effect (2–4). On page 787 of this issue, Hosten and Kwiat (5) use “weak measurement,” a controversial procedure from the foundations of quantum mechanics, to amplify this spin Hall effect in light (SHEL) rather than detecting it directly. In their experiment, they boost the tiny shift by a factor of 10,000, detecting it for the first time and characterizing it at the angstrom scale. This realizes one of the long-standing promises of weak measurement and demonstrates its potential in precision measurements.