Tilt Measurement at the Quantum Cramer–Rao Bound Using a Higher-Order Hermite–Gaussian Mode

The quantum Cramer–Rao bound (QCRB) provides an ultimate precision limit in parameter estimation. The sensitivity of spatial measurements can be improved by using the higher-order Hermite–Gaussian mode. However, to date, the QCRB-saturating tilt measurement has not been realized. Here, we experiment...

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Main Authors: Zhi Li, Yijian Wang, Hengxin Sun, Kui Liu, Jiangrui Gao
Format: Article
Language:English
Published: MDPI AG 2023-05-01
Series:Photonics
Subjects:
Online Access:https://www.mdpi.com/2304-6732/10/5/584
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author Zhi Li
Yijian Wang
Hengxin Sun
Kui Liu
Jiangrui Gao
author_facet Zhi Li
Yijian Wang
Hengxin Sun
Kui Liu
Jiangrui Gao
author_sort Zhi Li
collection DOAJ
description The quantum Cramer–Rao bound (QCRB) provides an ultimate precision limit in parameter estimation. The sensitivity of spatial measurements can be improved by using the higher-order Hermite–Gaussian mode. However, to date, the QCRB-saturating tilt measurement has not been realized. Here, we experimentally demonstrate tilt measurements using a higher-order <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><msub><mi>G</mi><mn>40</mn></msub></mrow></semantics></math></inline-formula> mode as the probe beam. Using the balanced homodyne detection with an optimal local beam, which involves the superposition of high-order <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><msub><mi>G</mi><mn>30</mn></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><msub><mi>G</mi><mn>50</mn></msub></mrow></semantics></math></inline-formula> modes, we demonstrate the precision of the tilt measurement approaching the QCRB. The signal-to-noise ratio of the tilt measurement is enhanced by 9.2 dB compared with the traditional method using <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><msub><mi>G</mi><mn>00</mn></msub></mrow></semantics></math></inline-formula> as the probe beam. This scheme is more practical and robust to losses, which has potential applications in areas such as laser interferometer gravitational-wave observatories and high-sensitivity atomic force microscopes.
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spelling doaj.art-2de5e535ae5442be944b15af53e601102023-11-18T02:54:49ZengMDPI AGPhotonics2304-67322023-05-0110558410.3390/photonics10050584Tilt Measurement at the Quantum Cramer–Rao Bound Using a Higher-Order Hermite–Gaussian ModeZhi Li0Yijian Wang1Hengxin Sun2Kui Liu3Jiangrui Gao4State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, ChinaState Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, ChinaState Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, ChinaState Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, ChinaState Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, ChinaThe quantum Cramer–Rao bound (QCRB) provides an ultimate precision limit in parameter estimation. The sensitivity of spatial measurements can be improved by using the higher-order Hermite–Gaussian mode. However, to date, the QCRB-saturating tilt measurement has not been realized. Here, we experimentally demonstrate tilt measurements using a higher-order <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><msub><mi>G</mi><mn>40</mn></msub></mrow></semantics></math></inline-formula> mode as the probe beam. Using the balanced homodyne detection with an optimal local beam, which involves the superposition of high-order <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><msub><mi>G</mi><mn>30</mn></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><msub><mi>G</mi><mn>50</mn></msub></mrow></semantics></math></inline-formula> modes, we demonstrate the precision of the tilt measurement approaching the QCRB. The signal-to-noise ratio of the tilt measurement is enhanced by 9.2 dB compared with the traditional method using <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>H</mi><msub><mi>G</mi><mn>00</mn></msub></mrow></semantics></math></inline-formula> as the probe beam. This scheme is more practical and robust to losses, which has potential applications in areas such as laser interferometer gravitational-wave observatories and high-sensitivity atomic force microscopes.https://www.mdpi.com/2304-6732/10/5/584high-order Hermite–Gaussian modetilt measurementquantum Cramer–Rao boundhomodyne detection
spellingShingle Zhi Li
Yijian Wang
Hengxin Sun
Kui Liu
Jiangrui Gao
Tilt Measurement at the Quantum Cramer–Rao Bound Using a Higher-Order Hermite–Gaussian Mode
Photonics
high-order Hermite–Gaussian mode
tilt measurement
quantum Cramer–Rao bound
homodyne detection
title Tilt Measurement at the Quantum Cramer–Rao Bound Using a Higher-Order Hermite–Gaussian Mode
title_full Tilt Measurement at the Quantum Cramer–Rao Bound Using a Higher-Order Hermite–Gaussian Mode
title_fullStr Tilt Measurement at the Quantum Cramer–Rao Bound Using a Higher-Order Hermite–Gaussian Mode
title_full_unstemmed Tilt Measurement at the Quantum Cramer–Rao Bound Using a Higher-Order Hermite–Gaussian Mode
title_short Tilt Measurement at the Quantum Cramer–Rao Bound Using a Higher-Order Hermite–Gaussian Mode
title_sort tilt measurement at the quantum cramer rao bound using a higher order hermite gaussian mode
topic high-order Hermite–Gaussian mode
tilt measurement
quantum Cramer–Rao bound
homodyne detection
url https://www.mdpi.com/2304-6732/10/5/584
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AT yijianwang tiltmeasurementatthequantumcramerraoboundusingahigherorderhermitegaussianmode
AT hengxinsun tiltmeasurementatthequantumcramerraoboundusingahigherorderhermitegaussianmode
AT kuiliu tiltmeasurementatthequantumcramerraoboundusingahigherorderhermitegaussianmode
AT jiangruigao tiltmeasurementatthequantumcramerraoboundusingahigherorderhermitegaussianmode