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Journal of Biomedical Optics Nov 2019The mesh-based Monte Carlo (MMC) algorithm is increasingly used as the gold-standard for developing new biophotonics modeling techniques in 3-D complex tissues,...
The mesh-based Monte Carlo (MMC) algorithm is increasingly used as the gold-standard for developing new biophotonics modeling techniques in 3-D complex tissues, including both diffusion-based and various Monte Carlo (MC)-based methods. Compared to multilayered and voxel-based MCs, MMC can utilize tetrahedral meshes to gain improved anatomical accuracy but also results in higher computational and memory demands. Previous attempts of accelerating MMC using graphics processing units (GPUs) have yielded limited performance improvement and are not publicly available. We report a highly efficient MMC-MMCL-using the OpenCL heterogeneous computing framework and demonstrate a speedup ratio up to 420× compared to state-of-the-art single-threaded CPU simulations. The MMCL simulator supports almost all advanced features found in our widely disseminated MMC software, such as support for a dozen of complex source forms, wide-field detectors, boundary reflection, photon replay, and storing a rich set of detected photon information. Furthermore, this tool supports a wide range of GPUs/CPUs across vendors and is freely available with full source codes and benchmark suites at http://mcx.space/#mmc.
Topics: Algorithms; Computer Graphics; Computer Simulation; Computers; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Monte Carlo Method; Optical Imaging; Optics and Photonics; Photons; Reproducibility of Results; Software
PubMed: 31746154
DOI: 10.1117/1.JBO.24.11.115002 -
The Review of Scientific Instruments Aug 2009We review the current state of multiphoton microscopy. In particular, the requirements and limitations associated with high-speed multiphoton imaging are considered. A... (Review)
Review
We review the current state of multiphoton microscopy. In particular, the requirements and limitations associated with high-speed multiphoton imaging are considered. A description of the different scanning technologies such as line scan, multifoci approaches, multidepth microscopy, and novel detection techniques is given. The main nonlinear optical contrast mechanisms employed in microscopy are reviewed, namely, multiphoton excitation fluorescence, second harmonic generation, and third harmonic generation. Techniques for optimizing these nonlinear mechanisms through a careful measurement of the spatial and temporal characteristics of the focal volume are discussed, and a brief summary of photobleaching effects is provided. Finally, we consider three new applications of multiphoton microscopy: nonlinear imaging in microfluidics as applied to chemical analysis and the use of two-photon absorption and self-phase modulation as contrast mechanisms applied to imaging problems in the medical sciences.
Topics: Absorption; Algorithms; Animals; Fluorescence; Humans; Microscopy, Fluorescence, Multiphoton; Models, Theoretical; Nonlinear Dynamics; Optics and Photonics; Photobleaching; Photons; Time Factors
PubMed: 19725639
DOI: 10.1063/1.3184828 -
Nano Letters Jan 2021Subwavelength nanostructures with tunable compositions and geometries show favorable optical functionalities for the implementation of nanophotonic systems. Precise and...
Subwavelength nanostructures with tunable compositions and geometries show favorable optical functionalities for the implementation of nanophotonic systems. Precise and versatile control of structural configurations on solid substrates is essential for their applications in on-chip devices. Here, we report all-solid-phase reconfigurable chiral nanostructures with silicon nanoparticles and nanowires as the building blocks in which the configuration and chiroptical response can be tailored on-demand by dynamic manipulation of the silicon nanoparticle. We reveal that the optical chirality originates from the handedness-dependent coupling between optical resonances of the silicon nanoparticle and the silicon nanowire via numerical simulations and coupled-mode theory analysis. Furthermore, the coexisting electric and magnetic resonances support strong enhancement of optical near-field chirality, which enables label-free enantiodiscrimination of biomolecules in single nanostructures. Our results not only provide insight into the design of functional high-index materials but also bring new strategies to develop adaptive devices for photonic and electronic applications.
Topics: Nanoparticles; Nanostructures; Optics and Photonics; Photons; Silicon
PubMed: 33372805
DOI: 10.1021/acs.nanolett.0c03957 -
Optics Express Aug 2010Holographic microscopy is increasingly recognized as a promising tool for the study of the central nervous system. Here we present a "holographic module", a simple...
Holographic microscopy is increasingly recognized as a promising tool for the study of the central nervous system. Here we present a "holographic module", a simple optical path that can be combined with commercial scanheads for simultaneous imaging and uncaging with structured two-photon light. The present microscope is coupled to two independently tunable lasers and has two principal configurations: holographic imaging combined with galvo-steered uncaging and holographic uncaging combined with conventional scanning imaging. We applied this flexible system for simultaneous two-photon imaging and photostimulation of neuronal cells with complex light patterns, opening new perspectives for the study of brain function in situ and in vivo.
Topics: Animals; Brain; Diagnostic Imaging; Equipment Design; Light; Mice; Mice, Inbred C57BL; Microscopy, Fluorescence; Neurons; Optics and Photonics; Photons; Polylysine; Silicon; Software
PubMed: 20940765
DOI: 10.1364/OE.18.018720 -
Nature Communications Jun 2022Nanostructures similar to those found in the vividly blue wings of Morpho butterflies and colorful photonic crystals enable structural color through constructive...
Nanostructures similar to those found in the vividly blue wings of Morpho butterflies and colorful photonic crystals enable structural color through constructive interference of light waves. Different from commonly studied structure-colored materials using periodic structures to manipulate optical properties, we report a previously unrecognized approach to precisely control the structural color and light transmission via a novel photonic colloidal gel without long-range order. Nanoparticles in this gel form micrometer-sized bicontinuous domains driven by the microphase separation of binary solvents. This approach enables dynamic coloration with a precise wavelength selectivity over a broad range of wavelengths extended well beyond the visible light that is not achievable with traditional methods. The dynamic wavelength selectivity is thermally tunable, reversible, and the material fabrication is easily scalable.
Topics: Animals; Butterflies; Nanostructures; Optics and Photonics; Photons; Wings, Animal
PubMed: 35750660
DOI: 10.1038/s41467-022-31020-0 -
Nature Methods Mar 2020Multiphoton microscopy has gained enormous popularity because of its unique capacity to provide high-resolution images from deep within scattering tissue. Here, we...
Multiphoton microscopy has gained enormous popularity because of its unique capacity to provide high-resolution images from deep within scattering tissue. Here, we demonstrate video-rate multiplane imaging with two-photon microscopy by performing near-instantaneous axial scanning while maintaining three-dimensional micrometer-scale resolution. Our technique, termed reverberation microscopy, enables the monitoring of neuronal populations over large depth ranges and can be implemented as a simple add-on to a conventional design.
Topics: Acoustics; Animals; Brain; Female; Imaging, Three-Dimensional; Mice; Mice, Inbred C57BL; Microscopy, Fluorescence, Multiphoton; Motor Cortex; Neurons; Olfactory Bulb; Optics and Photonics; Phantoms, Imaging; Photons; Scattering, Radiation; Signal-To-Noise Ratio
PubMed: 32042186
DOI: 10.1038/s41592-019-0728-9 -
Nature Communications Aug 2022While nanoscale quantum emitters are effective tags for measuring biomolecular interactions, their utilities for applications that demand single-unit observations are...
While nanoscale quantum emitters are effective tags for measuring biomolecular interactions, their utilities for applications that demand single-unit observations are limited by the requirements for large numerical aperture (NA) objectives, fluorescence intermittency, and poor photon collection efficiency resulted from omnidirectional emission. Here, we report a nearly 3000-fold signal enhancement achieved through multiplicative effects of enhanced excitation, highly directional extraction, quantum efficiency improvement, and blinking suppression through a photonic crystal (PC) surface. The approach achieves single quantum dot (QD) sensitivity with high signal-to-noise ratio, even when using a low-NA lens and an inexpensive optical setup. The blinking suppression capability of the PC improves the QDs on-time from 15% to 85% ameliorating signal intermittency. We developed an assay for cancer-associated miRNA biomarkers with single-molecule resolution, single-base mutation selectivity, and 10-attomolar detection limit. Additionally, we observed differential surface motion trajectories of QDs when their surface attachment stringency is altered by changing a single base in a cancer-specific miRNA sequence.
Topics: Blinking; MicroRNAs; Optics and Photonics; Photons; Quantum Dots
PubMed: 35941132
DOI: 10.1038/s41467-022-32387-w -
ACS Sensors Jul 2020Despite the recent emergence of microcavity resonators as label-free biological and chemical sensors, practical applications still require simple and robust methods to...
Despite the recent emergence of microcavity resonators as label-free biological and chemical sensors, practical applications still require simple and robust methods to impart chemical selectivity and reduce the cost of fabrication. We introduce the use of hydrocarbon-in-fluorocarbon-in-water (HC/FC/W) double emulsions as a liquid top cladding that expands the versatility of optical resonators as chemical sensors. The all-liquid complex emulsions are tunable droplets that undergo dynamic and reversible morphological transformations in response to a change in the chemical environment (., exposure to targeted analytes). This chemical-morphological coupling drastically modifies the effective refractive index, allowing the complex emulsions to act as a chemical transducer and signal amplifier. We detect this large change in the refractive index by tracking the shift of the enveloped resonant spectrum of a silicon nitride (SiN) racetrack resonator-based sensor, which correlates well with a change in the morphology of the complex droplets. This combination of soft materials (dynamic complex emulsions) and hard materials (on-chip resonators) provides a unique platform for liquid-phase, real-time, and continuous detection of chemicals and biomolecules for miniaturized and remote, environmental, medical, and wearable sensing applications.
Topics: Emulsions; Optics and Photonics; Photons; Refractometry; Transducers
PubMed: 32441524
DOI: 10.1021/acssensors.0c00399 -
Optics Express Jul 2022We demonstrate a miniature fiber-optic two two-photon endomicroscopy with microsphere-spliced double-cladding antiresonant fiber for resolution enhancement. An...
We demonstrate a miniature fiber-optic two two-photon endomicroscopy with microsphere-spliced double-cladding antiresonant fiber for resolution enhancement. An easy-to-operate process for fixing microsphere permanently in an antiresonant fiber core, by arc discharge, is proposed. The flexible fiber-optic probe is integrated with a parameter of 5.8 mm × 49.1 mm (outer diameter × rigid length); the field of view is 210 µm, the resolution is 1.3 µm, and the frame rate is 0.7 fps. The imaging ability is verified using ex-vivo mouse kidney, heart, stomach, tail tendon, and in-vivo brain neural imaging.
Topics: Animals; Fiber Optic Technology; Mice; Microspheres; Photons
PubMed: 36236806
DOI: 10.1364/OE.461325 -
Journal of Applied Biomaterials &... Jun 2017Sodium copper chlorophyllin (SCC), as one of the derivatives of chlorophyll - with its inherent green features; good stability for heat, light, acids and alkalies;...
BACKGROUND
Sodium copper chlorophyllin (SCC), as one of the derivatives of chlorophyll - with its inherent green features; good stability for heat, light, acids and alkalies; unique antimicrobial capability; and particular deodori zation performance - is widely applied in some fields such as the food industry, medicine and health care, daily cosmetic industry etc. SCC, as one of the metal porphyrins, has attracted much attention because of its unique electronic band structure and photon conversion performance. To promote the application of SCC in materials science; energy research and photonics, such as fast optical communications; and its use in nonlinear optical materials, solar photovoltaic cells, all-optical switches, optical limiters and saturable absorbers, great efforts should be dedicated to studying its nonlinear optical (NLO) properties.
METHODS
In this study, the absorption spectra and NLO properties of SCC in aqueous solution at different concentrations were measured. The Z-scan technique was used to determine NLO properties.
RESULTS
The results indicated that the absorption spectra of SCC exhibit 2 characteristic absorption peaks located at the wavelengths 405 and 630 nm, and the values of the peaks increase with increasing SCC concentration. The results also showed that SCC exhibits reverse saturation absorption and negative nonlinear refraction (self-defocusing).
CONCLUSIONS
It can be seen that SCC has good optical nonlinearity which will be convenient for applications in materials science, energy research and photonics.
Topics: Chlorophyllides; Hot Temperature; Light; Nonlinear Dynamics; Optics and Photonics; Photons; Surface Properties
PubMed: 28525677
DOI: 10.5301/jabfm.5000350