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Yuan J, Du P, Yang F, Quan W, Li J. Simultaneous improvement of the sensitivity and resolution of CPT magnetometers based on phase delay and differential method. OPTICS LETTERS 2024; 49:3858-3861. [PMID: 39008726 DOI: 10.1364/ol.528628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Accepted: 06/05/2024] [Indexed: 07/17/2024]
Abstract
We report a method to enhance the sensitivity of coherent population trapping (CPT) magnetometers using a combination of left-handed and right-handed circularly polarized light phase-delay detection and a differential detection scheme. The approach can achieve a four third-fold enhancement of the CPT dispersion signal slope and a three-fold reduction in noises. The proposed method experimentally exhibits a four third-fold magnetic field resolution enhancement in CPT open-loop measurements, and the differential method could achieve a sensitivity of 1 p T/H z at 10 Hz and a sensitivity of 0.4 p T/H z at 50-100 Hz in the CPT closed-loop measurement, which is a four-fold sensitivity enhancement compared to the single-transmitted CPT magnetometer.
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Sui X, He Z, Chu D, Cao L. Non-convex optimization for inverse problem solving in computer-generated holography. LIGHT, SCIENCE & APPLICATIONS 2024; 13:158. [PMID: 38982035 PMCID: PMC11233576 DOI: 10.1038/s41377-024-01446-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 03/27/2024] [Accepted: 04/07/2024] [Indexed: 07/11/2024]
Abstract
Computer-generated holography is a promising technique that modulates user-defined wavefronts with digital holograms. Computing appropriate holograms with faithful reconstructions is not only a problem closely related to the fundamental basis of holography but also a long-standing challenge for researchers in general fields of optics. Finding the exact solution of a desired hologram to reconstruct an accurate target object constitutes an ill-posed inverse problem. The general practice of single-diffraction computation for synthesizing holograms can only provide an approximate answer, which is subject to limitations in numerical implementation. Various non-convex optimization algorithms are thus designed to seek an optimal solution by introducing different constraints, frameworks, and initializations. Herein, we overview the optimization algorithms applied to computer-generated holography, incorporating principles of hologram synthesis based on alternative projections and gradient descent methods. This is aimed to provide an underlying basis for optimized hologram generation, as well as insights into the cutting-edge developments of this rapidly evolving field for potential applications in virtual reality, augmented reality, head-up display, data encryption, laser fabrication, and metasurface design.
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Affiliation(s)
- Xiaomeng Sui
- Department of Precision Instruments, Tsinghua University, Beijing, 100084, China
- Department of Engineering, Centre for Photonic Devices and Sensors, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK
| | - Zehao He
- Department of Precision Instruments, Tsinghua University, Beijing, 100084, China
| | - Daping Chu
- Department of Engineering, Centre for Photonic Devices and Sensors, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK.
- Cambridge University Nanjing Centre of Technology and Innovation, 23 Rongyue Road, Jiangbei New Area, Nanjing, 210000, China.
| | - Liangcai Cao
- Department of Precision Instruments, Tsinghua University, Beijing, 100084, China.
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Makowski M, Bomba J, Frej A, Kolodziejczyk M, Sypek M, Shimobaba T, Ito T, Kirilyuk A, Stupakiewicz A. Dynamic complex opto-magnetic holography. Nat Commun 2022; 13:7286. [PMID: 36435872 PMCID: PMC9701213 DOI: 10.1038/s41467-022-35023-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 11/15/2022] [Indexed: 11/28/2022] Open
Abstract
Despite recent significant progress in real-time, large-area computer-generated holography, its memory requirements and computational loads will be hard to tackle for several decades to come with the current paradigm based on a priori calculations and bit-plane writing to a spatial light modulator. Here we experimentally demonstrate a holistic approach to serial computation and repeatable writing of computer-generated dynamic holograms without Fourier transform, using minimal amounts of computer memory. We use the ultrafast opto-magnetic recording of holographic patterns in a ferrimagnetic film with femtosecond laser pulses, driven by the on-the-fly hardware computation of a single holographic point. The intensity-threshold nature of the magnetic medium allows sub-diffraction-limited, point-by-point toggling of arbitrarily localized magnetic spots on the sample, according to the proposed circular detour-phase encoding, providing complex modulation and symmetrical suppression of upper diffractive orders and conjugated terms in holographically reconstructed 3-D images.
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Affiliation(s)
- M Makowski
- Faculty of Physics, Warsaw University of Technology, 75 Koszykowa, 00-662, Warsaw, Poland.
| | - J Bomba
- Faculty of Physics, University of Bialystok, 1L Ciolkowskiego, 15-245, Bialystok, Poland
| | - A Frej
- Faculty of Physics, University of Bialystok, 1L Ciolkowskiego, 15-245, Bialystok, Poland
| | - M Kolodziejczyk
- Faculty of Physics, University of Bialystok, 1L Ciolkowskiego, 15-245, Bialystok, Poland
| | - M Sypek
- Faculty of Physics, Warsaw University of Technology, 75 Koszykowa, 00-662, Warsaw, Poland
| | - T Shimobaba
- Graduate School of Engineering, Chiba University, 1-33 Yayoi, Inage, Chiba, 263-8522, Japan
| | - T Ito
- Graduate School of Engineering, Chiba University, 1-33 Yayoi, Inage, Chiba, 263-8522, Japan
| | - A Kirilyuk
- FELIX Laboratory, Radboud University, 7 Toernooiveld, 6525 ED, Nijmegen, The Netherlands
| | - A Stupakiewicz
- Faculty of Physics, University of Bialystok, 1L Ciolkowskiego, 15-245, Bialystok, Poland.
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Peng X, Shi Y, Ren Z, Ying Y. Practical method for dynamic color holographic display. APPLIED OPTICS 2022; 61:9198-9202. [PMID: 36607054 DOI: 10.1364/ao.471751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 10/06/2022] [Indexed: 06/17/2023]
Abstract
A practical method for dynamic color holographic display by using a computer-generated hologram (CGH) with a high space-bandwidth product is proposed, and a dynamic color holographic display system is designed by a space-division method. First, three primary color CGHs of different frames from a color movie are fabricated on holographic recording material by a self-made CGH microfilming system. Secondly, the CGH is fixed on an X-Y moving stage, which is controlled by the system in order to bring the CGH to the appointed position. Thirdly, three primary color lasers are used to reconstruct the CGH. The switch of the lasers is controlled by the system synchronous with the X-Y moving stage. The color video with high quality can be obtained after filtering the three primary color reconstructed wavefronts. The experimental results demonstrate that the proposed dynamic color holographic display method is effective. It has practical application value in high-quality CGH display.
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Li YL, Li NN, Wang D, Chu F, Lee SD, Zheng YW, Wang QH. Tunable liquid crystal grating based holographic 3D display system with wide viewing angle and large size. LIGHT, SCIENCE & APPLICATIONS 2022; 11:188. [PMID: 35729102 PMCID: PMC9213428 DOI: 10.1038/s41377-022-00880-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/03/2022] [Accepted: 06/08/2022] [Indexed: 05/17/2023]
Abstract
As one of the most ideal display approaches, holographic 3-dimensional (3D) display has always been a research hotspot since the holographic images reproduced in such system are very similar to what humans see the actual environment. However, current holographic 3D displays suffer from critical bottlenecks of narrow viewing angle and small size. Here, we propose a tunable liquid crystal grating-based holographic 3D display system with wide viewing angle and large size. Our tunable liquid crystal grating, providing an adjustable period and the secondary diffraction of the reconstructed image, enables to simultaneously implement two different hologram generation methods in achieving wide viewing angle and enlarged size, respectively. By using the secondary diffraction mechanism of the tunable liquid crystal grating, the proposed system breaks through the limitations of narrow viewing angle and small size of holographic 3D display. The proposed system shows a viewing angle of 57.4°, which is nearly 7 times of the conventional case with a single spatial light modulator, and the size of the reconstructed image is enlarged by about 4.2. The proposed system will have wide applications in medical diagnosis, advertising, education and entertainment and other fields.
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Affiliation(s)
- Yi-Long Li
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Nan-Nan Li
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Di Wang
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China.
| | - Fan Chu
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Sin-Doo Lee
- Display Technology Research Center, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Yi-Wei Zheng
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Qiong-Hua Wang
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China.
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Abstract
Holographic three-dimensional (3D) display can be made very large using a modular system that allows seamless spatial tiling of multiple coarse integral holographic images.
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Li J, Smithwick Q, Chu D. Correction to: Holobricks: modular coarse integral holographic displays. LIGHT, SCIENCE & APPLICATIONS 2022; 11:82. [PMID: 35354787 PMCID: PMC8967883 DOI: 10.1038/s41377-022-00771-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Affiliation(s)
- Jin Li
- Centre for Photonic Devices and Sensors, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK
| | | | - Daping Chu
- Centre for Photonic Devices and Sensors, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK.
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