scholarly journals A stage-scanning two-photon microscope equipped with a temporal and a spatial pulse shaper: Enhance fluorescence signal by phase shaping

2018 ◽  
Vol 89 (12) ◽  
pp. 123701
Author(s):  
Frederik Büchau ◽  
Alexander Patas ◽  
Yang Yang ◽  
Albrecht Lindinger ◽  
Karsten Heyne
Keyword(s):  
Fluorescence Signal ◽  
Pulse Shaper ◽  
Two Photon ◽  
Stage Scanning

scholarly journals High-speed volumetric two-photon fluorescence imaging of neurovascular dynamics

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiang Lan Fan ◽  
Jose A. Rivera ◽  
Wei Sun ◽  
John Peterson ◽  
Henry Haeberle ◽  
...  
Keyword(s):  
Blood Flow ◽  
High Speed ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Fluorescence Signal ◽  
Imaging Method ◽  
Spatiotemporal Resolution ◽  
Two Photon

AbstractUnderstanding the structure and function of vasculature in the brain requires us to monitor distributed hemodynamics at high spatial and temporal resolution in three-dimensional (3D) volumes in vivo. Currently, a volumetric vasculature imaging method with sub-capillary spatial resolution and blood flow-resolving speed is lacking. Here, using two-photon laser scanning microscopy (TPLSM) with an axially extended Bessel focus, we capture volumetric hemodynamics in the awake mouse brain at a spatiotemporal resolution sufficient for measuring capillary size and blood flow. With Bessel TPLSM, the fluorescence signal of a vessel becomes proportional to its size, which enables convenient intensity-based analysis of vessel dilation and constriction dynamics in large volumes. We observe entrainment of vasodilation and vasoconstriction with pupil diameter and measure 3D blood flow at 99 volumes/second. Demonstrating high-throughput monitoring of hemodynamics in the awake brain, we expect Bessel TPLSM to make broad impacts on neurovasculature research.

Investigation of 6S 1/2–8S 1/2 two-photon transition of cesium atoms by a single 822 nm laser

2021 ◽  
Vol 19 (2) ◽  
pp. 025201
Author(s):  
Ning Liu ◽  
Sandan Wang ◽  
Jinpeng Yuan ◽  
Lirong Wang ◽  
Liantuan Xiao ◽  
...  
Keyword(s):  
Frequency Standard ◽  
Laser Beams ◽  
Fluorescence Signal ◽  
Frequency Reference ◽  
Two Photon ◽  
Photon Transition ◽  
Fabry Perot ◽  
Experimental Parameters ◽  
Stable Frequency ◽  
Vapor Temperature

Abstract We experimentally investigate the 6S 1/2–8S 1/2 two-photon transition in cesium vapor by a single laser. A blue (455.5 and 459.3 nm) fluorescence signal is observed as a result of 822.5 nm laser beams illuminating the Cs vapor with a counter-propagating configuration. The dependences of the fluorescence intensity on the polarization combinations of the laser beams, laser power and vapor temperature are studied to obtain optimal experimental parameters. The frequency difference between the two hyperfine components of 4158 (7) MHz is measured with a Fabry–Perot interferometer as a frequency reference. Such a large spectral isolation and the insensitivity to the Earth’s magnetic field enable the 6S 1/2–8S 1/2 transition to be a stable frequency standard candidate for a frequency-doubled 1644 nm laser in the U-band window for quantum telecommunication.

scholarly journals Multidither coherent optical adaptive technique for deep tissue two-photon microscopy

2019 ◽  
Vol 12 (04) ◽  
pp. 1942003 ◽  
Author(s):  
Biwei Zhang ◽  
Wei Gong ◽  
Chenxue Wu ◽  
Lejia Hu ◽  
Xinpei Zhu ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Diffraction Theory ◽  
Fluorescence Signal ◽  
Two Photon Microscopy ◽  
Scalar Diffraction ◽  
Two Photon ◽  
Scalar Diffraction Theory ◽  
Adaptive Technique ◽  
Photon Imaging ◽  
Two Photon Imaging

Two-photon microscopy normally suffers from the scattering of the tissue in biological imaging. Multidither coherent optical adaptive technique (COAT) can correct the scattered wavefront in parallel. However, the determination of the corrective phases may not be completely accurate using conventional method, which undermines the performance of this technique. In this paper, we theoretically demonstrate a method that can obtain more accurate corrective phases by determining the phase values from the square root of the fluorescence signal. A numerical simulation model is established to study the performance of adaptive optics in two-photon microscopy by combining scalar diffraction theory with vector diffraction theory. The results show that the distortion of the wavefront can be corrected more thoroughly with our method in two-photon imaging. In our simulation, with the scattering from a 450-[Formula: see text]m-thick mouse brain tissue, excitation focal spots with higher peak-to-background ratio (PBR) and images with higher contrast can be obtained. Hence, further enhancement of the multidither COAT correction performance in two-photon imaging can be expected.

scholarly journals Multiview Deconvolution Two-photon Laser Scanning Microscopy

2020 ◽  
Author(s):  
Dimitrios Kapsokalyvas ◽  
Rodrigo Rosas ◽  
Rob Janssen ◽  
Jo Vanoevelen ◽  
Martin Strauch ◽  
...  
Keyword(s):  
Second Harmonic ◽  
Light Sheet ◽  
Laser Scanning Microscopy ◽  
Three Dimensions ◽  
Scanning Microscopy ◽  
Fluorescence Signal ◽  
Microscopy Imaging ◽  
Two Photon ◽  
Light Sheet Microscopy ◽  
3D Image Reconstruction

Abstract Imaging in three dimensions is necessary for thick tissues and small organisms. This is possible with tomographic optical microscopy techniques such as confocal, two-photon and light sheet microscopy. All these techniques suffer from anisotropic resolution and limited penetration depth. In the past, Multiview microscopy - imaging the sample from different angles followed by 3D image reconstruction - was developed to address this issue for light sheet microscopy based on fluorescence signal. In this study we applied this methodology to accomplish Multiview imaging with two-photon microscopy based on fluorescence and additionally second harmonic signal from myosin and collagen. It was shown that isotropic resolution was achieved, the entirety of the sample was visualized, and interference artifacts were suppressed allowing clear visualization of collagen fibrils and myofibrils. This method can be applied to any scanning microscopy technique without microscope modifications. It can be used for imaging tissue and whole mount small organisms such as heart tissue, and zebrafish larva in 3D, label-free or stained, with at least 3-fold axial resolution improvement which can be significant for the accurate quantification of small 3D structures.

scholarly journals Nonlinear optical spectroscopy and two-photon excited fluorescence spectroscopy reveal the excited states of fluorophores embedded in a beetle’s elytra

2018 ◽  
Vol 9 (1) ◽  
pp. 20180052 ◽  
Author(s):  
Sébastien R. Mouchet ◽  
Charlotte Verstraete ◽  
Dimitrije Mara ◽  
Stijn Van Cleuvenbergen ◽  
Ewan D. Finlayson ◽  
...  
Keyword(s):  
Excited States ◽  
Nonlinear Optical ◽  
Polarization State ◽  
Polarized Light ◽  
Fluorescence Emission ◽  
Biological Tissues ◽  
Optical Measurements ◽  
Fluorescence Signal ◽  
Photonic Structure ◽  
Two Photon

Upon illumination by ultraviolet light, many animal species emit light through fluorescence processes arising from fluorophores embedded within their biological tissues. Fluorescence studies in living organisms are however relatively scarce and so far limited to the linear regime. Multiphoton excitation fluorescence analyses as well as nonlinear optical techniques offer unique possibilities to investigate the effects of the local environment on the excited states of fluorophores. Herein, these techniques are applied for the first time to study of the naturally controlled fluorescence in insects. The case of the male Hoplia coerulea beetle is investigated because the scales covering the beetle’s elytra are known to possess an internal photonic structure with embedded fluorophores, which controls both the beetle’s coloration and the fluorescence emission. An intense two-photon excitation fluorescence signal is observed, the intensity of which changes upon contact with water. A third-harmonic generation signal is also detected, the intensity of which depends on the light polarization state. The analysis of these nonlinear optical and fluorescent responses unveils the multi-excited states character of the fluorophore molecules embedded in the beetle’s elytra. The role of form anisotropy in the photonic structure, which causes additional tailoring of the beetle’s optical responses, is demonstrated by circularly polarized light and nonlinear optical measurements.

Theoretical design and investigation of 1,8-naphthalimide-based two-photon fluorescent probes for detecting cytochrome P450 1A with separated fluorescence signal

2018 ◽  
Vol 20 (19) ◽  
pp. 13290-13305 ◽  
Author(s):  
Chun Zhang ◽  
Ai-Min Ren ◽  
Jing-Fu Guo ◽  
Dan Wang ◽  
Li-Ying Yu
Keyword(s):  
Cytochrome P450 ◽  
Fluorescent Probe ◽  
Fluorescent Probes ◽  
Fluorescence Signal ◽  
Two Photon ◽  
Theoretical Design ◽  
Cytochrome P450 1A

Two-photon fluorescent probe for detecting CYP1A enzyme with separated fluorescence signal.

scholarly journals A novel spheroid model for preclinical intercellular nanophotosensitizer-mediated tumor study

2018 ◽  
pp. 14-20
Author(s):  
YuS Maklygina ◽  
ID Romanishkin ◽  
AV Ryabova ◽  
IV Yakavec ◽  
L Bolotin ◽  
...  
Keyword(s):  
Cell Cultures ◽  
3D Structure ◽  
3D Cell Culture ◽  
3D Models ◽  
Fluorescence Signal ◽  
Phenotypic Properties ◽  
Two Photon ◽  
Tumor Study ◽  
Photon Excitation ◽  
Insight Into

Aluminum phthalocyanine nanoparticles (NP AlPc) possess the features that make them a promising photosensitizer. In particular, AlPc NPs do not fluoresce in free nanoform, fluoresce weakly in normal tissue, strongly in tumors and very strongly in macrophages. Also, such particles fluoresce and become phototoxic when contacting certain biocomponents. The type of biocomponents that bind to AlPc NPS defines intensity, lifetime, and spectral distribution of the fluorescence. This study aimed to investigate the peculiarities of nanophotosensitizer capturing in 3D models of cell cultures. The data obtained demonstrate that AlPc NPs are captured by cells inside the spheroid in the course of the first hour, as the fluorescent signal's growth shows. Having analyzed the fluctuations of the fluorescence signal of AlPc NPs inside a spheroid, we have also discovered that the cellular 3D models are heterogeneous. Laser irradiation (two-photon excitation at λ = 780/390 nm) resulted in photobleaching of fluorescence, which is probably associated with AlPc NP deactivation. Thus, the created model comprised of a 3D cell culture and AlPc NPs provides a better insight into metabolic processes in cells than monolayer 2D cell cultures. Besides, the model allows to evaluate the photodynamic effect depending on phenotypic properties of various areas in the heterogeneous 3D-structure.

A fast responsive two-photon fluorescent probe for imaging H2O2 in lysosomes with a large turn-on fluorescence signal

2016 ◽  
Vol 79 ◽  
pp. 237-243 ◽  
Author(s):  
Mingguang Ren ◽  
Beibei Deng ◽  
Jian-Yong Wang ◽  
Xiuqi Kong ◽  
Zhan-Rong Liu ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Fluorescence Signal ◽  
Two Photon ◽  
Turn On

Label-free distinguishing between neurons and glial cells based on two-photon excited fluorescence signal of neuron perinuclear granules

2016 ◽  
Vol 13 (8) ◽  
pp. 085603 ◽  
Author(s):  
Huiping Du ◽  
Liwei Jiang ◽  
Xingfu Wang ◽  
Gaoqiang Liu ◽  
Shu Wang ◽  
...  
Keyword(s):  
Glial Cells ◽  
Fluorescence Signal ◽  
Label Free ◽  
Two Photon
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