Improving longitudinal resolution of Airy beams two-photon volume imaging with fluorescence lifetime imaging

Author(s):

Guo, Yong; Wang, Luwei; Zhu, Yinru; Gao, Xinwei; Weng, Xiaoyu; Liu, Jinyuan; Yan, Wei & Qu, Junle

Abstract:

“The non-diffracting Airy beams have been reported to increase acquisition speed by projecting the axially significantly elongated information to a two-dimensional (2D) image. Due to the elongated focal length, an Airy volumetric image can cover information as much as stack images with multiple Gaussian images at different imaging depths, which significantly increases the volumetric imaging rate. However, the projection of three-dimensional (3D) structures on a 2D plane is usually indistinguishable, especially those that overlap along the axis. Therefore, we proposed an axially resolved volume imaging technique based on a two-photon fluorescence lifetime microscopy imaging (FLIM) by using Airy beams.”

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Publication: Optics Communications
Issue/Year: Optics Communications, Volume 530; Pages 129151; 2023
DOI: 10.1016/j.optcom.2022.129151

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

Resolution and uniformity improvement of parallel confocal microscopy based on microlens arrays and a spatial light modulator

Author(s):

Luo, Tianpeng; Yuan, Jing; Chang, Jin; Dai, Yanfeng; Gong, Hui; Luo, Qingming & Yang, Xiaoquan

Abstract:

“In traditional fluorescence microscopy, it is hard to achieve a large uniform imaging field with high resolution. In this manuscript, we developed a confocal fluorescence microscope combining the microlens array with spatial light modulator to address this issue. In our system, a multi-spot array generated by a spatial light modulator passes through the microlens array to form an optical probe array. Then multi-spot adaptive pixel-reassignment method for image scanning microscopy (MAPR-ISM) will be introduced in this parallelized imaging to improve spatial resolution. To generate a uniform image, we employ an optimized double weighted Gerchberg–Saxton algorithm (ODWGS) using signal feedback from the camera. We have built a prototype system with a FOV of 3.5 mm × 3.5 mm illuminated by 2500 confocal points. The system provides a lateral resolution of ∼0.82 µm with ∼1.6 times resolution enhancement after ISM processing. And the nonuniformity across the whole imaging field is 3%. Experimental results of fluorescent beads, mouse brain slices and melanoma slices are presented to validate the applicability and effectiveness of our system.”

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Publication: Optics Express
Issue/Year: Optics Express, Volume 31; Number 3; Pages 4537; 2023
DOI: 10.1364/oe.478820

Modulation of Non-diffracting Hermite Gaussian Beams and Nonlinear Optical Microscopy for Nanoscale Sulfur Imaging

Author(s):

Navarro, Gilberto

Abstract:

“Hermite Gaussian beams are the solutions of the scalar paraxial wave equation in Cartesian coordinates. A method was developed to modulate the intensity profile of non-diffracting Hermite Gaussian (HG) beams. The original HG beams intensity profile consists of high intense corner lobes and low intense central lobes which is not ideal for structured illumination in light-field microscopy. The modulated HG beams were generated by multiplying the original HGâ??s beam envelope by a super-Gaussian envelope to modify the intensity profile to attain equal intensity lobes. The propagation of the original HG beam and modulated HG beam were compared to determine that the non-diffracting properties of the modulated HG beam were held.

Two-photon absorption (TPA) is a nonlinear optical process in which the absorption coefficient depends on the optical intensity. In the process of two-photon absorption, an atom makes a transition from its ground state to an excited state by the simultaneous (  1 fs) absorption of two photons. In the second project, two-photon microscopy was used to detect the root uptake and determine the biodistribution of nanoscale sulfur. Characterization of pristine, stearic acid coated, and bulk sulfur was done to determine their fluorescent signal properties. Tomatoes that were grown in nano-sulfur treated soils to enhance crop nutrition and suppress disease, were imagined under the two-photon microscope to detect the root uptake of the nanoscale sulfur.”

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Publication: University of Texas at El Paso, Thesis
Issue/Year: , 2022
URL: https://scholarworks.utep.edu/open_etd/3706

Ultrafast Transverse Modulation of Free Electrons by Interaction with Shaped Optical Fields

Author(s):

Madan, Ivan; Leccese, Veronica; Mazur, Adam; Barantani, Francesco; LaGrange, Thomas; Sapozhnik, Alexey; Tengdin, Phoebe M.; Gargiulo, Simone; Rotunno, Enzo; Olaya, Jean-Christophe; Kaminer, Ido; Grillo, Vincenzo; de Abajo, F. Javier Garcia; Carbone, Fabrizio & Vanacore, Giovanni Maria

Abstract:

“Spatiotemporal electron-beam shaping is a bold frontier of electron microscopy. Over the past decade, shaping methods evolved from static phase plates to low-speed electrostatic and magnetostatic displays. Recently, a swift change of paradigm utilizing light to control free electrons has emerged. Here, we experimentally demonstrate arbitrary transverse modulation of electron beams without complicated electron-optics elements or material nanostructures, but rather using shaped light beams. On-demand spatial modulation of electron wavepackets is obtained via inelastic interaction with transversely shaped ultrafast light fields controlled by an external spatial light modulator. We illustrate this method for the cases of Hermite-Gaussian and Laguerre-Gaussian modulation and discuss their use in enhancing microscope sensitivity. Our approach dramatically widens the range of patterns that can be imprinted on the electron profile and greatly facilitates tailored electron-beam shaping.”

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Publication: ACS Photonics
Issue/Year: ACS Photonics, 2022
DOI: 10.1021/acsphotonics.2c00850

High-resolution surface plasmon resonance holographic microscopy based on symmetrical excitation

Author(s):

Dou, Jiazhen; Dong, Chen; Dai, Siqing; Mi, Jingyu; Luo, Xiangyuan; Di, Jianglei; Zhang, Jiwei & Zhao, Jianlin

Abstract:

“Surface plasmon resonance holographic microscopy (SPRHM) is able to simultaneously obtain the amplitude- and phase-contrast surface plasmon resonance (SPR) images, showing great potentials in imaging near-field targets with high sensitivity. However, suffered by the decaying length of surface plasmon wave which can be as long as tens of microns, the spatial resolution of SPRHM is lower than that of traditional holographic microscopy. In this work, we propose to enhance the spatial resolution in SPRHM by exciting surface plasmon resonance in two symmetrical directions and detecting the complex amplitudes of the reflected light symmetrically. Through the Fourier analysis of the recorded composite hologram, the reconstruction schemes for high-resolution amplitude- and phase-contrast SPR images are established, respectively. The feasibility and advantages of the proposed method is verified by numerical simulations and experimental demonstrations of small-size particles and micro-structures.”

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Publication: Optics and Lasers in Engineering
Issue/Year: Optics and Lasers in Engineering, Volume 153; Pages 107000; 2022
DOI: 10.1016/j.optlaseng.2022.107000

Large depth-of-field fluorescence microscopy based on deep learning supported by Fresnel incoherent correlation holography

Author(s):

Wu, Peng; Zhang, Dejie; Yuan, Jing; Zeng, Shaoqun; Gong, Hui; Luo, Qingming & Yang, Xiaoquan

Abstract:

“Fluorescence microscopy plays an irreplaceable role in biomedicine. However, limited depth of field (DoF) of fluorescence microscopy is always an obstacle of image quality, especially when the sample is with an uneven surface or distributed in different depths. In this manuscript, we combine deep learning with Fresnel incoherent correlation holography to describe a method to obtain significant large DoF fluorescence microscopy. Firstly, the hologram is restored by the Auto-ASP method from out-of-focus to in-focus in double-spherical wave Fresnel incoherent correlation holography. Then, we use a generative adversarial network to eliminate the artifacts introduced by Auto-ASP and output the high-quality image as a result. We use fluorescent beads, USAF target and mouse brain as samples to demonstrate the large DoF of more than 400µm, which is 13 times better than that of traditional wide-field microscopy. Moreover, our method is with a simple structure, which can be easily combined with many existing fluorescence microscopic imaging technology”

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Publication: Optics Express
Issue/Year: Optics Express, Volume 30; Number 4; Pages 5177; 2022
DOI: 10.1364/oe.451409

Improving Multiphoton Microscopy by Combining Spherical Aberration Patterns and Variable Axicons

Author(s):

Bueno, J.M.; Hernández, G.; Skorsetz, M.; Artal, P.

Abstract:

“Multiphoton (MP) microscopy is a well-established method for the non-invasive imaging of biological tissues. However, its optical sectioning capabilities are reduced due to specimen-induced aberrations. Both the manipulation of spherical aberration (SA) and the use of axicons have been reported to be useful techniques to bypass this limitation. We propose the combination of SA patterns and variable axicons to further improve the quality of MP microscopy images. This approach provides enhanced images at different depth locations whose quality is better than those corresponding to the use of SA or axicons separately. Thus, the procedure proposed herein facilitates the visualization of details and increases the depth observable at high resolution.”

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Publication: Photonics
Issue/Year: Photonics, Volume 8; Number 12; Pages 573; 2021
DOI: 10.3390/photonics8120573

Complex-amplitude single-pixel imaging using coherent structured illumination

Author(s):

Hou, Hong-Yun; Zhao, Ya-Nan; Han, Jia-Cheng; Cui, Sheng-Wei; Cao, De-Zhong; Liu, Hong-Chao; Zhang, Su-Heng & Liang, Bao-Lai

Abstract:

“This research presents a coherent structured illumination single-pixel imaging scheme to image objects with complex amplitudes. By utilizing a phase-only spatial light modulator for phase modulation, we can efficiently generate the Hadamard basis structured light and the reference light that interfere with each other to form the coherent structured illumination. Using the 4-step phase-shifting, the spectrum of the object is acquired by detecting the zero-frequency component of the object light with a single-pixel photodetector. The desired complex-amplitude image can be further retrieved by applying an inverse Hadamard transform. The proposed scheme is experimentally demonstrated by imaging two etched glass objects, a dragonfly wing, and a resolution test chart. Benefiting from the phase modulation, this scheme has a high efficiency, a high imaging quality, a high spatial resolution, and a simple and stable configuration to obtain both the phase and amplitude information of the target object. The proposed scheme provides a promising complex-amplitude imaging modality with single-pixel detection. Thus it might find broad applications in optical metrology and biomedical science.”

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Publication: Optics Express
Issue/Year: Optics Express, Volume 29; Number 25; Pages 41827; 2021
DOI: 10.1364/oe.443258

Axial resolution enhancement for planar Airy beam light-sheet microscopy via the complementary beam subtraction method

Author(s):

Liu, Chao; Yu, Xianghua; Bai, Chen; Li, Xing; Zhou, Yuan; Yan, Shaohui; Min, Junwei; Dan, Dan; Li, Runze; Gu, Shuangyu & Yao, Baoli

Abstract:

“Airy beam light-sheet illumination can extend the field of view (FOV) of light-sheet fluorescence microscopy due to the unique propagation properties of non-diffraction and self-acceleration. However, the side lobes create undesirable out-of-focus background, leading to poor axial resolution and low image contrast. Here, we propose an Airy complementary beam subtraction (ACBS) method to improve the axial resolution while keeping the extended FOV. By scanning the optimized designed complementary beam that has two main lobes (TML), the generated complementary light-sheet has almost identical intensity distribution to that of the planar Airy light-sheet except for the central lobe. Subtraction of the two images acquired by double exposure respectively using the planar Airy light-sheet and the planar TML light-sheet can effectively suppress the influence of the out-of-focus background. The axial resolution improves from ∼4µm to 1.2 µm. The imaging performance was demonstrated by imaging specimens of aspergillus conidiophores and GFP labeled mouse brain section. The results show that the ACBS method enables the Airy beam light-sheet fluorescence microscopy to obtain better imaging quality.”

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Publication: Applied Optics
Issue/Year: Applied Optics, Volume 60; Number 32; Pages 10239; 2021
DOI: 10.1364/ao.441070
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