Velocity measurements with structured light transmitted through a multimode optical fiber using digital optical phase conjugation

Author(s):

Lars Büttner and Martin Thümmler and Jürgen Czarske

Abstract:

“Lensless fiber microendoscopes enable optical diagnostics and therapy with minimal
invasiveness. Because of their small diameters, multimode fibers are ideal candidates, but mode
scrambling hinders the transmission of structured light fields. We present the generation of a
localized fringe system at variable distances from the distal fiber end by exploiting digital optical
phase conjugation. The replayed fringe system was used for quantitative metrology. Velocity
measurements of a microchannel flow in the immediate proximity of the fiber end without the
use of any imaging lenses are shown. Lensless multimode fiber systems are of interest especially
for biomedical imaging and stimulation as well as technical inspection and flow measurements. ”

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Publication: Optics Express

Issue/Year/DOI: Vol. 28, Issue 6, pp. 8064-8075
DOI: 10.1364/OE.386047

Encoding of arbitrary micrometric complex illumination patterns with reduced speckle

Author(s):

Miguel Carbonell-Leal, Gladys Mínguez-Vega, Jesús Lancis, and Omel Mendoza-Yero

Abstract:

“In nonlinear microscopy, phase-only spatial light modulators (SLMs) allow achieving simultaneous two-photon excitation and fluorescence emission from specific region-of-interests (ROIs). However, as iterative Fourier transform algorithms (IFTAs) can only approximate the illumination of selected ROIs, both image formation and/or signal acquisition can be largely affected by the spatial irregularities of the illumination patterns and the speckle noise. To overcome these limitations, we propose an alternative complex illumination method (CIM) able to generate simultaneous excitation of large-area ROIs with full control over the amplitude and phase of light and reduced speckle. As a proof-of-concept we experimentally demonstrate single-photon and second harmonic generation (SHG) with structured illumination over large-area ROIs.”

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Publication: Optics Express

Issue/Year/DOI: Vol. 27, Issue 14, pp. 19788-19801 (2019)
DOI: 10.1364/OE.27.019788

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/DOI: 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." Link to Publications Page

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

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/DOI: 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/DOI: 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/DOI: 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.”

Link to Publications Page

Publication: Micromachines

Issue/Year/DOI: 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.”

 

Link to Publications Page

Publication: Science

Issue/Year/DOI: 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.”

Link to Publications Page

Publication: Biomedical Optics Express

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

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