scholarly journals Multimodal nonlinear endomicroscopic imaging probe using a double-core double-clad fiber and focus-combining micro-optical concept

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Ekaterina Pshenay-Severin ◽  
Hyeonsoo Bae ◽  
Karl Reichwald ◽  
Gregor Matz ◽  
Jörg Bierlich ◽  
...  
Keyword(s):  
Second Harmonic ◽  
Numerical Aperture ◽  
Small Diameter ◽  
Field Of View ◽  
Tissue Imaging ◽  
Laser Source ◽  
High Peak Power ◽  
Label Free ◽  
Signal Collection ◽  
Non Linear

AbstractMultimodal non-linear microscopy combining coherent anti-Stokes Raman scattering, second harmonic generation, and two-photon excited fluorescence has proved to be a versatile and powerful tool enabling the label-free investigation of tissue structure, molecular composition, and correlation with function and disease status. For a routine medical application, the implementation of this approach into an in vivo imaging endoscope is required. However, this is a difficult task due to the requirements of a multicolour ultrashort laser delivery from a compact and robust laser source through a fiber with low losses and temporal synchronization, the efficient signal collection in epi-direction, the need for small-diameter but highly corrected endomicroobjectives of high numerical aperture and compact scanners. Here, we introduce an ultra-compact fiber-scanning endoscope platform for multimodal non-linear endomicroscopy in combination with a compact four-wave mixing based fiber laser. The heart of this fiber-scanning endoscope is an in-house custom-designed, single mode, double clad, double core pure silica fiber in combination with a 2.4 mm diameter NIR-dual-waveband corrected endomicroscopic objective of 0.55 numerical aperture and 180 µm field of view for non-linear imaging, allowing a background free, low-loss, high peak power laser delivery, and an efficient signal collection in backward direction. A linear diffractive optical grating overlays pump and Stokes laser foci across the full field of view, such that diffraction-limited performance is demonstrated for tissue imaging at one frame per second with sub-micron spatial resolution and at a high transmission of 65% from the laser to the specimen using a distal resonant fiber scanner.

scholarly journals Non-linear label-free imaging through a multimode graded index optical fibre

2020 ◽  
Vol 238 ◽  
pp. 04006
Author(s):  
Angel Cifuentes ◽  
Johanna Trägårdh ◽  
Tomáš Pikálek ◽  
Mojmír Šerý ◽  
Denis Akimov ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Second Harmonic ◽  
Speckle Pattern ◽  
Label Free ◽  
Graded Index ◽  
Non Linear ◽  
Wavefront Shaping ◽  
Microscopy Techniques ◽  
Anti Stokes ◽  
Made In

In recent years, great advances have been made in developing minimal footprint micro-endoscopes using multimode optical fibres (MMF) [1]. By employing wavefront shaping methods the seemingly random speckle pattern resulting from the guiding of coherent light through an MMF can be formed into a diffraction limited spot. This enables the implementation of multiple laser scanning techniques. In this work we show that this approach can be employed to realize label-free non-linear microscopy techniques such as coherent anti-Stokes Raman scattering (CARS) and second harmonic generation (SHG). Backscattered light makes epi-detection possible even though these processes preferably emit light in the direction of beam propagation [2].

scholarly journals Visualization and Analysis of Whole Depot Adipose Tissue Innervation

2019 ◽  
Author(s):  
Jake W. Willows ◽  
Magdalena Blaszkiewicz ◽  
Amy Lamore ◽  
Samuel Borer ◽  
Amanda L. Dubois ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Second Harmonic ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Light Sheet ◽  
Tissue Imaging ◽  
Label Free ◽  
Adipose Tissues ◽  
Light Sheet Microscopy ◽  
Neurite Density

AbstractAdipose tissue requires neural innervation in order to regulate important metabolic functions. Though seminal work on adipose denervation has underscored the importance of adipose-nerve interactions in both white (energy storing) and brown (energy expending) adipose tissues, much remains a mystery. This is due, in part, to the inability to effectively visualize the various nerve subtypes residing within these tissues and to gain a comprehensive quantitation of neurite density in an entire depot. With the recent surge of advanced imaging techniques such as light sheet microscopy and optical clearing procedures, adipose tissue imaging has been reinvigorated with a focus on three-dimensional analysis of tissue innervation. However, clearing techniques are time consuming, often require solvents caustic to objective lenses, alter tissue morphology, and greatly reduce fluorophore lifespan. Not only are current methods of imaging wholemount adipose tissues inconvenient, but often attempts to quantify neurite density across physiological or pathophysiological conditions have been limited to representative section sampling. We have developed a new method of adipose tissue neurite imaging and quantitation that is faster than current clearing-based methods, does not require caustic chemicals, and leaves the tissue fully intact. Maintenance of a fully intact depot allowed for tiling z-stacks and producing maximum intensity projections of the entire adipose depot, which were then used to quantify neurite density across the tissue. With this processing method we were able to characterize the nerves, nerve-subtypes, and neurovascular interactions within the inguinal subcutaneous white adipose tissue in mice using up to five fluorescent channels at high resolution. We also utilized second harmonic generation, which provides label-free imaging, to investigate collagen fiber abundance in adipose of obese mice.

Non-linear optical behavior of benzothiazole based chromophores: Second harmonic generation

2020 ◽  
Vol 183 ◽  
pp. 108739
Author(s):  
Shivani ◽  
Ishpreet Kaur ◽  
Karthika Chemmanghattu ◽  
Paramjit Kaur ◽  
Kamaljit Singh
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Non Linear ◽  
Linear Optical ◽  
Optical Behavior

scholarly journals An Optical Frequency Domain Angle Measurement Method Based on Second Harmonic Generation

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 670
Author(s):  
Wijayanti Dwi Astuti ◽  
Hiraku Matsukuma ◽  
Masaru Nakao ◽  
Kuangyi Li ◽  
Yuki Shimizu ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Second Harmonic Generation ◽  
Frequency Domain ◽  
Harmonic Generation ◽  
Measurement Method ◽  
Second Harmonic ◽  
Angle Measurement ◽  
Laser Source ◽  
Optical Frequency ◽  
Measurable Range

This paper proposes a new optical angle measurement method in the optical frequency domain based on second harmonic generation with a mode-locked femtosecond laser source by making use of the unique characteristic of the high peak power and wide spectral range of the femtosecond laser pulses. To get a wide measurable range of angle measurement, a theoretical calculation for several nonlinear optical crystals is performed. As a result, LiNbO3 crystal is employed in the proposed method. In the experiment, the validity of the use of a parabolic mirror is also demonstrated, where the chromatic aberration of the focusing beam caused the localization of second harmonic generation in our previous research. Moreover, an experimental demonstration is also carried out for the proposed angle measurement method. The measurable range of 10,000 arc-seconds is achieved.

scholarly journals 1700 nm optical coherence microscopy enables minimally invasive, label-free, in vivo optical biopsy deep in the mouse brain

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jun Zhu ◽  
Hercules Rezende Freitas ◽  
Izumi Maezawa ◽  
Lee-way Jin ◽  
Vivek J. Srinivasan
Keyword(s):  
Minimally Invasive ◽  
Mouse Brain ◽  
Numerical Aperture ◽  
Optical Biopsy ◽  
Optical Coherence ◽  
Label Free ◽  
Optical Coherence Microscopy ◽  
Minimal Invasiveness ◽  
Cortical Regions

AbstractIn vivo, minimally invasive microscopy in deep cortical and sub-cortical regions of the mouse brain has been challenging. To address this challenge, we present an in vivo high numerical aperture optical coherence microscopy (OCM) approach that fully utilizes the water absorption window around 1700 nm, where ballistic attenuation in the brain is minimized. Key issues, including detector noise, excess light source noise, chromatic dispersion, and the resolution-speckle tradeoff, are analyzed and optimized. Imaging through a thinned-skull preparation that preserves intracranial space, we present volumetric imaging of cytoarchitecture and myeloarchitecture across the entire depth of the mouse neocortex, and some sub-cortical regions. In an Alzheimer’s disease model, we report that findings in superficial and deep cortical layers diverge, highlighting the importance of deep optical biopsy. Compared to other microscopic techniques, our 1700 nm OCM approach achieves a unique combination of intrinsic contrast, minimal invasiveness, and high resolution for deep brain imaging.

scholarly journals Advanced Label-Free Laser Scanning Microscopy and Its Biological Imaging Application

2021 ◽  
Vol 11 (3) ◽  
pp. 1002
Author(s):  
Xue Wang ◽  
Xinchao Lu ◽  
Chengjun Huang
Keyword(s):  
Laser Scanning ◽  
Second Harmonic ◽  
Biological Tissues ◽  
Biological Imaging ◽  
Laser Scanning Microscopy ◽  
Scanning Microscopy ◽  
Localized Surface Plasmon ◽  
Label Free ◽  
Coherent Raman ◽  
Surface Plasmon Microscopy

By eliminating the photodamage and photobleaching induced by high intensity laser and fluorescent molecular, the label-free laser scanning microscopy shows powerful capability for imaging and dynamic tracing to biological tissues and cells. In this review, three types of label-free laser scanning microscopies: laser scanning coherent Raman scattering microscopy, second harmonic generation microscopy and scanning localized surface plasmon microscopy are discussed with their fundamentals, features and recent progress. The applications of label-free biological imaging of these laser scanning microscopies are also introduced. Finally, the performance of the microscopies is compared and the limitation and perspectives are summarized.

scholarly journals Nonlinear Solution to a Non-Fourier Heat Conduction Problem in a Slab Heated by Laser Source

2016 ◽  
Vol 63 (1) ◽  
pp. 129-144
Author(s):  
Mohammad Javad Noroozi ◽  
Seyfolah Saedodin ◽  
Davood Domiri Ganji
Keyword(s):  
Heat Conduction ◽  
Heat Conduction Problem ◽  
Adomian Decomposition Method ◽  
Laser Source ◽  
Temperature Dependent ◽  
Conduction Model ◽  
Non Linear Equation ◽  
Adomian Decomposition ◽  
Non Linear ◽  
Fourier Heat Conduction

Abstract The effect of laser, as a heat source, on a one-dimensional finite body was studied in this paper. The Cattaneo-Vernotte non-Fourier heat conduction model was used for thermal analysis. The thermal conductivity was assumed temperature-dependent which resulted in a non-linear equation. The obtained equations were solved using the approximate-analytical Adomian Decomposition Method (ADM). It was concluded that the non-linear analysis is important in non-Fourier heat conduction problems. Significant differences were observed between the Fourier and non-Fourier solutions which stresses the importance of non-Fourier solutions in the similar problems.

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