Endogenous SHG and 2PEF coherence imaging of substructures in neurons in 3D

Author(s):

Carlos Macias-Romero, Claire Teulon, Marie Didier, and Sylvie Roke

Abstract:

“Neuronal morphology, long-distance transport and signalling critically depend on the organization of microtubules in the cytoskeleton. Second harmonic generation (SHG) imaging has been recognized as a potentially powerful tool for in situ label-free neuroimaging with specific sensitivity to microtubules. We study here the structural organization of microtubules in living neurons using a wide-field multiphoton microscope that performs 3D imaging using a structured illumination. This microscope allows label-free high throughput imaging of living mammalian neurons. We show that we can image structural correlations by taking advantage of the structured illumination and the coherence of the emitted light. The result allows us to study the microtubule organization throughout the development of the neuron and to differentiate between the regions of the cytoskeleton in the matured neuron.”

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Publication: Optics Express
Issue/Year: Vol. 27, Issue 3, pp. 2235-2247 (2019)
DOI: 10.1364/OE.27.002235

Raman imaging through multimode sapphire fiber

Author(s):

Sunan Deng, Damien Loterie, Georgia Konstantinou, Demetri Psaltis, and Christophe Moser
Abstract:

“We report on a sapphire fiber Raman imaging probe’s use for challenging applications where access is severely restricted. Small-dimension Raman probes have been developed previously for various clinical applications because they show great capability for diagnosing disease states in bodily fluids, cells, and tissues. However, applications of these sub-millimeter diameter Raman probes were constrained by two factors: first, it is difficult to incorporate filters and focusing optics at such small scale; second, the weak Raman signal is often obscured by strong background noise from the fiber probe material, especially the most commonly used silica, which has a strong broad background noise in low wavenumbers (<500-1700 cm−1). Here, we demonstrate the thinnest-known imaging Raman probe with a 60 μm diameter Sapphire multimode fiber in which both excitation and signal collection pass through. This probe takes advantage of the low fluorescence and narrow Raman peaks of Sapphire, its inherent high temperature and corrosion resistance, and large numerical aperture (NA). Raman images of Polystyrene beads, carbon nanotubes, and CaSO4 agglomerations are obtained with a spatial resolution of 1 μm and a field of view of 30 μm. Our imaging results show that single polystyrene bead (~15 µm diameter) can be differentiated from a mixture with CaSO4 agglomerations, which has a close Raman shift.”

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Publication: Optics Express
Issue/Year: Vol. 27, Issue 2, pp. 1090-1098 (2019)
DOI: 10.1364/OE.27.001090

Aberration correction for improving the image quality in STED microscopy using the genetic algorithm

Author(s):

Luwei Wang, Wei Yan, Runze Li, Xiaoyu Weng, Jia Zhang, Zhigang Yang, Liwei Liu, Tong Ye and Junle Qu

Abstract:

“With a purely optical modulation of fluorescent behaviors, stimulated emission depletion (STED) microscopy allows for far-field imaging with a diffraction-unlimited resolution in theory. The performance of STED microscopy is affected by many factors, of which aberrations induced by the optical system and biological samples can distort the wave front of the depletion beam at the focal plane to greatly deteriorate the spatial resolution and the image contrast. Therefore, aberration correction is imperative for STED imaging, especially for imaging thick specimens. Here, we present a wave front compensation approach based on the genetic algorithm (GA) to restore the distorted laser wave front for improving the quality of STED images. After performing aberration correction on two types of zebrafish samples, the signal intensity and the imaging resolution of STED images were both improved, where the thicknesses were 24 μm and 100 μm in the zebrafish retina sample and the zebrafish embryo sample, respectively. The results showed that the GA-based wave front compensation approach has the capability of correction for both system-induced and sample-induced aberrations. The elimination of aberrations can prompt STED imaging in deep tissues; therefore, STED microscopy can be expected to play an increasingly important role in super-resolution imaging related to the scientific research in biological fields.”

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Publication: Nanophotonics Volume 7: Issue 12
Issue/Year: Volume 7: Issue 12
DOI: 10.1515/nanoph-2018-0133

Nonlinear generation of Airy vortex beam

Author(s):
Hui Li and Haigang Liu and Xianfeng Chen

Abstract:

“Recently, hybrid beams have sparked considerable interest because of their properties coming from different kinds of beams at the same time. Here, we experimentally demonstrate Airy vortex beam generation in the nonlinear frequency conversion process when the fundamental wave with its phase modulated by a spatial light modulator is incident into a homogeneous nonlinear medium. In our experiments, second harmonic Airy circle vortex beams and Airy ellipse vortex beams were generated and the topological charge was also measured. The parabolic trajectory of those Airy vortex beams can be easily adjusted by altering the fundamental wave phase. This study provides a simple way to generate second harmonic Airy vortex beams, which may broaden its future use in optical manipulation and light-sheet microscopy.”

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Publication: Optics Express
Issue/Year: Optics Express Volume 26, Issue 16
DOI: 10.1364/oe.26.021204

Multiple-plane image formation by Walsh zone plates

Author(s):

Federico Machado, Vicente Ferrando, Fernando Giménez, Walter D. Furlan, and Juan A. Monsoriu

Abstract:

“A radial Walsh filter is a phase binary diffractive optical element characterized by a set of concentric rings that take the phase values 0 or π, corresponding to the values + 1 or −1 of a given radial Walsh function. Therefore, a Walsh filter can be re-interpreted as an aperiodic multifocal zone plate, capable to produce images of multiple planes simultaneously in a single output plane of an image forming system. In this paper, we experimentally demonstrate for the first time the focusing capabilities of these structures. Additionally, we report the first achievement of images of multiple-plane objects in a single image plane with these aperiodic diffractive lenses.”

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Publication: Optics Express
Issue/Year: Optics Express Volume 26, Issue 16
DOI: 10.1364/OE.26.021210

Wide-field in situ multiplexed Raman imaging with superresolution

Author(s):

Houkai Chen and Xiaojing Wu and Yuquan Zhang and Yong Yang and Changjun Min and Siwei Zhu and Xiaocong Yuan and Qiaoliang Bao and Jing Bu

Abstract:

“Because of the fingerprint-like specificity of its characteristic spectrogram, Raman spectral imaging has been applied widely in various research areas. Using a combination of structured illumination with the surfaceenhanced Raman scattering (SERS) technique, wide-field Raman imaging is developed with a significant improvement in spatial resolution. As a result of the relatively narrow Raman characteristic peaks, optically encoded SERS nanoparticles can be used to perform multiplexed imaging. The results show excellent superresolution wide-field multiplexed imaging performance. The developed technique has extraordinary potential for applications in biological imaging and other related fields.”

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Publication: Photonics Research
Issue/Year: Photonics Research Volume 6, Issue 6 pp. 530-534
DOI: 10.1364/PRJ.6.000530

Micro-Dumbbells—A Versatile Tool for Optical Tweezers

Author(s):

Weronika Lamperska, Sławomir Drobczyński, Michał Nawrot, Piotr Wasylczyk, Jan Masajada

Abstract:

“Manipulation of micro- and nano-sized objects with optical tweezers is a well-established, albeit still evolving technique. While many objects can be trapped directly with focused laser beam(s), for some applications indirect manipulation with tweezers-operated tools is preferred. We introduce a simple, versatile micro-tool operated with holographic optical tweezers. The 40 µm long dumbbell-shaped tool, fabricated with two-photon laser 3D photolithography has two beads for efficient optical trapping and a probing spike on one end. We demonstrate fluids viscosity measurements and vibration detection as examples of possible applications.”

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Publication: Micromachines
Issue/Year: Micromachines Volume 9, Issue 6
DOI: 10.3390/mi9060277

Observing the cell in its native state: Imaging subcellular dynamics in multicellular organisms

Author(s):

Liu, Tsung-Li and Upadhyayula, Srigokul and Milkie, Daniel E. and Singh, Ved and Wang, Kai and Swinburne, Ian A. and Mosaliganti, Kishore R. and Collins, Zach M. and Hiscock, Tom W. and Shea, Jamien and Kohrman, Abraham Q. and Medwig, Taylor N. and Dambournet, Daphne and Forster, Ryan and Cunniff, Brian and Ruan, Yuan and Yashiro, Hanako and Scholpp, Steffen and Meyerowitz, Elliot M. and Hockemeyer, Dirk and Drubin, David G. and Martin, Benjamin L. and Matus, David Q. and Koyama, Minoru and Megason, Sean G. and Kirchhausen, Tom and Betzig, Eric

Abstract:

“True physiological imaging of subcellular dynamics requires studying cells within their parent organisms, where all the environmental cues that drive gene expression, and hence the phenotypes that we actually observe, are present. A complete understanding also requires volumetric imaging of the cell and its surroundings at high spatiotemporal resolution, without inducing undue stress on either. We combined lattice light-sheet microscopy with adaptive optics to achieve, across large multicellular volumes, noninvasive aberration-free imaging of subcellular processes, including endocytosis, organelle remodeling during mitosis, and the migration of axons, immune cells, and metastatic cancer cells in vivo. The technology reveals the phenotypic diversity within cells across different organisms and developmental stages and may offer insights into how cells harness their intrinsic variability to adapt to different physiological environments.”

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Publication: Science
Issue/Year: Science, Vol. 360, Issue 6386, (2018)
DOI: 10.1126/science.aaq1392

Single shot, three-dimensional fluorescence microscopy with a spatially rotating point spread function

Author(s):

Zhaojun Wang and Yanan Cai and Yansheng Liang and Xing Zhou and Shaohui Yan and Dan Dan and Piero R. Bianco and Ming Lei and Baoli Yao

Abstract:

“A wide-field fluorescence microscope with a double-helix point spread function (PSF) is constructed to obtain the specimen’s three-dimensional distribution with a single snapshot. Spiral-phase-based computer-generated holograms (CGHs) are adopted to make the depth-of-field of the microscope adjustable. The impact of system aberrations on the double-helix PSF at high numerical aperture is analyzed to reveal the necessity of the aberration correction. A modified cepstrum-based reconstruction scheme is promoted in accordance with properties of the new double-helix PSF. The extended depth-of-field images and the corresponding depth maps for both a simulated sample and a tilted section slice of bovine pulmonary artery endothelial (BPAE) cells are recovered, respectively, verifying that the depth-of-field is properly extended and the depth of the specimen can be estimated at a precision of 23.4nm. This three-dimensional fluorescence microscope with a framerate-rank time resolution is suitable for studying the fast developing process of thin and sparsely distributed micron-scale cells in extended depth-of-field.”

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Publication: Biomedical Optics Express
Issue/Year: Biomedical Optics Express, Vol. 8, Issue 12, (2017)
DOI: 10.1364/BOE.8.005493

Deep tissue optical focusing and optogenetic modulation with time-reversed ultrasonically encoded light.

Author(s):

Ruan, Haowen; Brake, Joshua; Robinson, J. Elliott; Liu, Yan; Jang, Mooseok; Xiao, Cheng; Zhou, Chunyi; Gradinaru, Viviana & Yang, Changhuei

Abstract:

“Noninvasive light focusing deep inside living biological tissue has long been a goal in biomedical optics. However, the optical scattering of biological tissue prevents conventional optical systems from tightly focusing visible light beyond several hundred micrometers. The recently developed wavefront shaping technique time-reversed ultrasonically encoded (TRUE) focusing enables noninvasive light delivery to targeted locations beyond the optical diffusion limit. However, until now, TRUE focusing has only been demonstrated inside nonliving tissue samples. We present the first example of TRUE focusing in 2-mm-thick living brain tissue and demonstrate its application for optogenetic modulation of neural activity in 800-μm-thick acute mouse brain slices at a wavelength of 532 nm. We found that TRUE focusing enabled precise control of neuron firing and increased the spatial resolution of neuronal excitation fourfold when compared to conventional lens focusing. This work is an important step in the application of TRUE focusing for practical biomedical uses.”

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Publication: Science Advances
Issue/Year: Science Advances, Volume 3; Number 12; Pages 5520; 2017
DOI: 10.1126/sciadv.aao5520