Flow Cytometry with Anti-Diffraction Light Sheet (ADLS) by Spatial Light Modulation

Author(s):

Gong, Yanyan; Zeng, Ming; Zhu, Yueqiang; Li, Shangyu; Zhao, Wei; Zhang, Ce; Zhao, Tianyun; Wang, Kaige; Yang, Jiangcun & Bai, Jintao

Abstract:

“Flow cytometry is a widespread and powerful technique whose resolution is determined by its capacity to accurately distinguish fluorescently positive populations from negative ones. However, most informative results are discarded while performing the measurements of conventional flow cytometry, e.g., the cell size, shape, morphology, and distribution or location of labeled exosomes within the unpurified biological samples. Herein, we propose a novel approach using an anti-diffraction light sheet with anisotroic feature to excite fluorescent tags. Constituted by an anti-diffraction Bessel–Gaussian beam array, the light sheet is 12 μm wide, 12 μm high, and has a thickness of  0.8 μm . The intensity profile of the excited fluorescent signal can, therefore, reflect the size and allow samples in the range from O (100 nm ) to 10 μm (e.g., blood cells) to be transported via hydrodynamic focusing in a microfluidic chip. The sampling rate is 500 kHz, which provides a capability of high throughput without sacrificing the spatial resolution. Consequently, the proposed anti-diffraction light sheet flow cytometry (ADLSFC) can obtain more informative results than the conventional methodologies, and is able to provide multiple characteristics (e.g., the size and distribution of fluorescent signal) helping to distinguish the target samples from the complex backgrounds.”

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Publication: Micromachines
Issue/Year: Micromachines, Volume 14; Number 3; Pages 679; 2023
DOI: 10.3390/mi14030679

Computational holographic ghost diffraction

Author(s):

Ye, Zhiyuan; Hou, Wanting; Zhao, Jilun; Wang, Hai-Bo & Xiong, Jun

Abstract:

“Since the paradigm shift in 2009 from pseudo-thermal ghost imaging (GI) to computational GI using a spatial light modulator, computational GI has enabled image formation via a single-pixel detector and thus has a cost-effective advantage in some unconventional wave bands. In this Letter, we propose an analogical paradigm known as computational holographic ghost diffraction (CH-GD) to shift ghost diffraction (GD) from classical to computational by using self-interferometer-assisted measurement of field correlation functions rather than intensity correlation functions. More than simply “seeing” the diffraction pattern of an unknown complex volume object with single-point detectors, CH-GD can retrieve the diffracted light field’s complex amplitude and can thus digitally refocus to any depth in the optical link. Moreover, CH-GD has the potential to obtain the multimodal information including intensity, phase, depth, polarization, and/or color in a more compact and lensless manner.”

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Publication: Optics Letters
Issue/Year: Optics Letters, Volume 48; Number 7; Pages 1618; 2023
DOI: 10.1364/ol.484537

Encrypting orbital angular momentum holography with ghost imaging

Author(s):

Ma, Junyao; Li, Zhe; Zhao, Shengmei & Wang, Le

Abstract:

“In this paper, we propose a multiple images simultaneous encryption scheme by encrypting the orbital angular momentum (OAM) holography with ghost imaging. By controlling the topological charge of the incident OAM light beam on the OAM-multiplexing hologram, different images can be selectively obtained for ghost imaging (GI). Followed by the random speckles illumination, the bucket detector values in GI are obtained and then considered as the ciphertext transmitted to the receiver. The authorized user can distill the correct relationship between the bucket detections and the illuminating speckle patterns with the key and the additional topological charges, so that each holographic image can be successfully recovered, while the eavesdropper can not obtain any information about the holographic image without the key. The eavesdropper even can not get clear holographic image when all the key is eavesdropped but without topological charges. The experimental results show that the proposed encryption scheme has a higher capacity for multiple images because there is no theoretical topological charge limit for the selectivity of OAM holography, and the results also show that the proposed encryption scheme is more secure and has a stronger robustness. Our method may provide a promising avenue for multi-image encryption and has the potential for more applications.”

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Publication: Opt. Express
Issue/Year: Opt. Express, Volume 31; Number 7; Pages 11717–11728; 2023
DOI: 10.1364/OE.483923

Highly transparent wave front printed volume holograms realized by amplitude-modulated incoherent pre-illumination

Author(s):

Wilm, Tobias; Wieland, Max; Fiess, Reinhold & Stork, Wilhelm

Abstract:

“We present highly transparent, wave front printed volume holographic optical elements (vHOEs), realized with a new recording method based on the pre-illumination of incoherent light patterns. The introduced amplitudemodulated pattern illuminates a distinct area on the unexposed, photopolymer-based holographic recording material prior to the hologram recording sequence. The incoherent pre-illumination scheme enables a precise tuning of the material’s local photosensitivity without the formation of a holographic volume diraction grating. As a consequence, the pre-illumination exposure signicantly suppresses the formation of transparency diminishing structures in the material that are formed concurrently with the volume diraction grating during the hologram recording sequence. The pre-illumination component is integrated in an extended immersion-based wave front printing setup, which realizes vHOEs by sequentially recording single holographic elements in an array-like structure. A wide range of dierent recording congurations is enabled by our recording setup due to independent modulation of both wave fronts and the possibility to realize large o-axis recording angles. We introduce two hologram characterization methods, based on a diraction eciency and a slanted-edge method analysis, which are used to evaluate the implemented pre-illumination method and demonstrate signicant improvements to the see-through quality of the presented wave front recorded vHOEs.”

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Publication: Proc. SPIE 12445
Issue/Year: Proc. SPIE 12445, Practical Holography XXXVII: Displays, Materials, and Applications, 124450S, 2023
DOI: 10.1117/12.2647361

Multi-Depth Computer-Generated Hologram Based on Stochastic Gradient Descent Algorithm with Weighted Complex Loss Function and Masked Diffraction

Author(s):

Quan, Jiale; Yan, Binbin; Sang, Xinzhu; Zhong, Chongli; Li, Hui; Qin, Xiujuan; Xiao, Rui; Sun, Zhi; Dong, Yu & Zhang, Huming

Abstract:

“In this paper, we propose a method to generate multi-depth phase-only holograms using
stochastic gradient descent (SGD) algorithm with weighted complex loss function and masked multi-
layer diffraction. The 3D scene can be represented by a combination of layers in different depths. In
the wave propagation procedure of multiple layers in different depths, the complex amplitude of
layers in different depths will gradually diffuse and produce occlusion at another layer. To solve this
occlusion problem, a mask is used in the process of layers diffracting. Whether it is forward wave
propagation or backward wave propagation of layers, the mask can reduce the occlusion problem
between different layers. Otherwise, weighted complex loss function is implemented in the gradient
descent optimization process, which analyzes the real part, the imaginary part, and the amplitude
part of the focus region between the reconstructed images of the hologram and the target images. The
weight parameter is used to adjust the ratio of the amplitude loss of the focus region in the whole
loss function. The weight amplitude loss part in weighted complex loss function can decrease the
interference of the focus region from the defocus region. The simulations and experiments have
validated the effectiveness of the proposed method.”

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Publication: Micromachines
Issue/Year: Micromachines, Volume 14; Number 3; Pages 605; 2023
DOI: 10.3390/mi14030605

Wavefront Sensing by a Common-Path Interferometer for Wavefront Correction in Phase and Amplitude by a Liquid Crystal Spatial Light Modulator Aiming the Exoplanet Direct Imaging

Author(s):

Yudaev, Andrey; Kiselev, Alexander; Shashkova, Inna; Tavrov, Alexander; Lipatov, Alexander & Korablev, Oleg

Abstract:

“We implemented the common-path achromatic interfero-coronagraph both for the wavefront sensing and the on-axis image component suppression, aiming for the stellar coronagraphy. A common-path achromatic interfero-coronagraph has its optical scheme based on a nulling rotational-shear interferometer. The angle of rotational shear can be chosen at a small angular extent of about 10 deg. Such a small angular shear maintains the coronagraphic contrast degradation known as the stellar leakage effect, caused by a finite stellar size. We study the phase and amplitude wavefront control by a liquid crystal spatial light modulator of reflection type which is used as the pixilated active adaptive optics unit. Therefore, adaptive optics perform a wavefront-correcting input toward a stellar interfero-coronagraph aiming at the direct exoplanet imaging. Presented here are both the numeric evaluations and the lab experiment stand to prove the declared functionality output.”

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Publication: Photonics
Issue/Year: Photonics, Volume 10; Number 3; Pages 320; 2023
DOI: 10.3390/photonics10030320

Color optimization of a full-color holographic stereogram printing system using a single SLM based on iterative exposure control

Author(s):

Khuderchuluun, Anar; Dashdavaa, Erkhembaatar; Rupali, Shindae; Kwon, Ki-Chul; Kang, Hoonjong; Lee, Kwon-Yeon & Kim, Nam

Abstract:

“In this paper, color optimization of a full-color holographic stereogram printing system using a single SLM based on iterative exposure is proposed. First, an array of sub-holograms (hogels) is generated effectively within fast computergenerated integral imaging, and fully analyzed phase-modulation for red, green, and blue (RGB) channels of hogel. Then, the generated hogels are recorded into holographic material sequentially where SLM displays the R, G, and B channels of a single hogel via effectual exposure under synchronized control with three electrical shutters for RGB laser illumination to obtain verified color optimization. Numerical simulation and optical reconstructions are implemented.”

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Publication: Proc. SPIE
Issue/Year: Proc. SPIE 12445, Practical Holography XXXVII: Displays, Materials, and Applications, 124450A (8 March 2023)
DOI: 10.1117/12.2651038

Solid-state 360° optical beamforming for reconfigurable multicast optical wireless communications

Author(s):

Zeng, Shihao; Zhang, Yanfeng; Liu, Junyi; Lin, Zhenrui; Lin, Zhongzheng; Chen, Hongjia; Liu, Jie & Yu, Siyuan

Abstract:

“Optical wireless communication is an attractive technique for data center interconnects due to its low latency line-of-sight connectivity. Multicast, on the other hand, is an important data center network function that can improve traffic throughput, reduce latency, and make efficient use of network resources. To enable reconfigurable multicast in data center optical wireless networks, we propose a novel 360° optical beamforming scheme based on the principle of superposition of orbital angular momentum modes, emitting beams from the source rack pointing towards any combination of other racks so that connections are established between the source and multiple destination racks. We experimentally demonstrate the scheme using solid state devices for a scenario where racks are arranged in a hexagonal formation in which a source rack can connect with any number of adjacent racks simultaneously, with each link transmitting 70 Gb/s on-off-keying modulations at bit error rates of <10−6 at 1.5-m and 2.0-m link distances.”

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Publication: Optics Express
Issue/Year: Optics Express, Volume 31; Number 6; Pages 10070; 2023
DOI: 10.1364/oe.477553

Mechanical-scan-free and multi-color super-resolutionimaging with diffractive spot array illumination

Author(s):

Xu, Ning; Bohndiek, Sarah E.; Li, Zexing; Zhang, Cilong & Tan, Qiaofeng

Abstract:

“Point-scanning microscopy approaches are transforming super-resolution imaging. Despite achieving parallel high-speed imaging using multifocal techniques, efficient multicolor capability with high-quality illumination is currently lacking. In this paper, we present for the first time Mechanical-scan-free and multi-Color Super-resolution Microscopy (MCoSM) by spot array illumination, which enables mechanical-scan-free super-resolution
imaging with adjustable resolution and field of view (FoV) based on spatial light modulators (SLMs). Through 100s-10,000s super-resolution spot illumination with different FoV for imaging, we demonstrate the adjustable capacity of MCoSM. MCoSM extends current spectral imaging capabilities through a time-sharing process of different color illumination with phase-shifting scanning, while retaining the spatial flexibility of super-resolution imaging with diffractive spot array illumination. To showcase the prospects for further combining MCoSM with multi-color imaging, we also perform spectral unmixing (four-colors) on images of fluorescent beads at high resolution. MCoSM provides a versatile platform
for studying molecular interactions in complex samples at the nanoscale level.”

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Publication: arXiv
Issue/Year: arXiv, 2023
DOI: https://arxiv.org/ftp/arxiv/papers/2303/2303.06988.pdf

Curve-shaped ultrashort laser pulses with programmable spatiotemporal behavior

Author(s):

Enar Franco, Óscar Martínez-Matos, and José A. Rodrigo

Abstract:

“Structured ultrashort laser pulses with controlled spatiotemporal properties are emerging as a key tool for the study and application of light–matter interactions in different fields such as microscopy, time-resolved imaging, laser micromachining, particle acceleration, and attosecond science. In practice, a structured ultrashort pulse focused along a target trajectory with controlled pulse dynamics is required, e.g., to set the trajectory and velocity of the resulting intensity peak. Here, to address this challenging problem, we present a technique and experimental setup that allows straightforward engineering of structured ultrashort laser pulses with control of their spatiotemporal properties enabling tailored pulse propagation dynamics along the target trajectory. Our theoretical framework describes the design and control of this kind of curve-shaped laser pulse in terms of the curve geometry and phase prescribed along it. We have derived a closed-form expression that describes the interplay between the curve geometry and prescribed phase governing the pulse dynamics, including the temporal behavior of the pulse peak intensity while preserving the pulse duration. The theoretical results and the corresponding numerical simulations allow us to analyze the pulse dynamics on the example of femtosecond curve-shaped vortex pulses, including contour-shaped pulses created to follow the outline of objects at micrometer scale. The experimental results demonstrate the generation of these structured ultrashort pulses. These findings could pave the way for the next generation of ultrashort laser-based optical tools for the study and control of light–matter interactions.”

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Publication: Optica
Issue/Year: Optica, Volume 10; Number 3; Pages 379–392; 2023
DOI: 10.1364/OPTICA.478086
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