Rapid tilted-plane Gerchberg-Saxton algorithm for holographic optical tweezers

Author(s):

Yanan Cai, Shaohui Yan, Zhaojun Wang, Runze Li, Yansheng Liang, Yuan Zhou, Xing Li, Xianghua Yu, Ming Lei and Baoli Yao

Abstract:

“Benefitting from the development of commercial spatial light modulator (SLM), holographic optical tweezers (HOT) have emerged as a powerful tool for life science, material science and particle physics. The calculation of computer-generated holograms (CGH) for generating multi-focus arrays plays a key role in HOT for trapping of a bunch of particles in parallel. To realize dynamic 3D manipulation, we propose a new tilted-plane GS algorithm for fast generation of multiple foci. The multi-focal spots with a uniformity of 99% can be generated in a tilted plane. The computation time for a CGH with 512512 pixels is less than 0.1 second.
We demonstrated the power of the algorithm by simultaneously trapping and rotating silica beads with a 77 spots array in three dimensions. The presented algorithm is expected as a powerful kernel of HOT.”

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Publication: Optics Express
Issue/Year: Vol. 28, Issue 9, pp. 12729-12739
DOI: 10.1364/OE.389897

Anomalous ring-connected optical vortex array

Author(s):

Xinzhong Li and Hao Zhang

Abstract:

“In this study, an anomalous ring-connected optical vortex array (ARC-OVA) via the superposition of two grafted optical vortices (GOVs) with different topological charges (TCs) has been proposed. Compared with conventional OVAs, the signs and distribution of the OVs can be individually modulated, while the number of OVs remains unchanged. In particular, the positive and negative OVs simultaneously appear in the same intensity ring. Additionally, the size of the dark core occupied by the OV can be modulated, and the specific dark core is shared by a pair of plus–minus OVs. This work deepens our knowledge about connected OVAs and facilitates new potential applications, especially in particle manipulation and optical measurement.”

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Publication: Optics Express
Issue/Year: Vol. 28, Issue 9, pp. 13775-13785
DOI: 10.1364/OE.390985

Non-iterative phase hologram generation with optimized phase modulation

Author(s):

Lizhi Chen, Hao Zhang, Liangcai Cao and Guofan Jin

Abstract:

“A non-iterative algorithm is proposed to generate phase holograms with optimized phase modulation. A quadratic initial phase with continuous distributed spectrum is utilized to iteratively optimize the phase modulation in the reconstruction plane, which can be used as an optimized phase distribution for arbitrary target images. The phase hologram can be calculated directly according to the modulated wave field distribution in the reconstruction plane. Fast generation of the phase holograms can be achieved by this non-iterative implementation, and the avoidance of the random phase modulation helps to suppress the speckle noise. Numerical and
optical experiments have demonstrated that the proposed method can efficiently generate phase holograms with quality reconstructions.”

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Publication: Optics Express
Issue/Year: Vol. 28, Issue 8, pp. 11380-11392
DOI: 10.1364/OE.391518

Entangled qutrits generated in four-wave mixing without post-selection

Author(s):

Shuai Shi, Ming-Xin Dong, Yi-Chen Yu, Ying-Hao Ye, Wei Zhang, Kai Wang, Guang-Can Guo, Dong-Sheng Ding and Bao-Sen Shi

Abstract:

“High-dimensional entangled states and quantum repeaters are important elements in efficient long-range quantum communications. The high-dimensional property associated with the orbital angular momentum (OAM) of each photon improves the bandwidth of the quantum communication network. However, the generation of high-dimensional entangled states by the concentration method reduces the brightness of the entangled light source, making extensions to these higher dimensions difficult. To overcome this difficulty, we propose to generate entangled qutrits in the OAM space by loading the pump light with OAM. Compared with the concentration method, our experimental results show that the rate of generation of photon pairs improves significantly with an observed 5.5-fold increase. The increased generation rate provides the system with the ability to resist the noise and improve the fidelity of the state. The S value of the Clauser–Horne–Shimony–Holt inequality increases from 2.48 ± 0.07 to 2.69 ± 0.04 under the same background noise, and the fidelity of the reconstructed density matrix improves from 57.8 ± 0.14% to 70 ± 0.17%. These achievements exhibit the enormous advantages of high-dimensional entanglement generation.”

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Publication: Optics Express
Issue/Year: Vol. 28, Issue 8, pp. 11538-11547
DOI: 10.1364/OE.383378