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https://www.readbyqxmd.com/read/29221053/ultra-high-speed-plif-imaging-for-simultaneous-visualization-of-multiple-species-in-turbulent-flames
#1
Zhenkan Wang, Panagiota Stamatoglou, Zheming Li, Marcus Aldén, Mattias Richter
In order to obtain more detailed characteristics and information in highly turbulent flames, for a better understanding of the transient behavior of eddies in such flames, a measurement technique with sufficient temporal resolution is requested. However, the probing of species distributions relevant in combustion (e.g. OH, CH2O) with ultra-high-speed laser diagnostics still remains a challenge. Nd:YAG clusters commercially available can generate only 4-8 pulses, although with high laser energy. Systems based on a diode-pumped solid-state Nd:YAG laser combined with a dye laser produce only about 100 μJ pulse energy at ultra-high repetition rates (≥50 kHz)...
November 27, 2017: Optics Express
https://www.readbyqxmd.com/read/29131193/frequency-and-timing-stability-of-an-airborne-injection-seeded-nd-yag-laser-system-for-direct-detection-wind-lidar
#2
Christian Lemmerz, Oliver Lux, Oliver Reitebuch, Benjamin Witschas, Christian Wührer
We report on the design and performance of the laser deployed in the airborne demonstrator Doppler wind lidar for the Aeolus mission of the European Space Agency (ESA). The all-solid-state, diode-pumped and frequency-tripled Nd:YAG laser is realized as a master oscillator power amplifier (MOPA) system, generating 60 mJ of single-frequency pulses at 355 nm wavelength, 50 Hz repetition rate and 20 ns pulse duration. For the measurement of the Doppler frequency shift over several accumulated laser shots, the frequency stability of the laser is of crucial importance...
November 10, 2017: Applied Optics
https://www.readbyqxmd.com/read/29105645/understanding-gan-ingan-core-shell-growth-towards-high-quality-factor-whispering-gallery-modes-from-non-polar-ingan-quantum-wells-on-gan-rods
#3
C Tessarek, S Rechberger, C Dieker, M Heilmann, E Spiecker, S Christiansen
GaN microrods are used as a basis for subsequent InGaN quantum well (QW) and quantum dot deposition by metal-organic vapor phase epitaxy. The coverage of the shell along the sidewall of rods is dependent on the rod growth time and a complete coverage is obtained for shorter rod growth times. Transmission electron microscopy measurements are performed to reveal the structural properties of the InGaN layer on the sidewall facet and on the top facet. The presence of layers in the microrod and on the microrod surface will be discussed with respect to GaN and InGaN growth...
November 6, 2017: Nanotechnology
https://www.readbyqxmd.com/read/29091666/high-depth-resolution-range-imaging-with-multiple-wavelength-superheterodyne-interferometry-using-1550-nm-lasers
#4
Fengqiang Li, Joshua Yablon, Andreas Velten, Mohit Gupta, Oliver Cossairt
Lasers and laser diodes are widely used as illumination sources for optical imaging techniques. Time-of-flight (ToF) cameras with laser diodes and range imaging based on optical interferometry systems using lasers are among these techniques, with various applications in fields such as metrology and machine vision. ToF cameras can have imaging ranges of several meters, but offer only centimeter-level depth resolution. On the other hand, range imaging based on optical interferometry has depth resolution on the micrometer and even nanometer scale, but offers very limited (sub-millimeter) imaging ranges...
November 1, 2017: Applied Optics
https://www.readbyqxmd.com/read/29077539/oxygen-enriched-photosensitizer-medium-with-red-blood-cells-to-study-tissue-interaction-of-photosensitization-reaction
#5
Risa Hamada, Emiyu Ogawa, Tsunenori Arai
BACKGROUND: It has been reported that the oxygen pressure of a photosensitizer medium decreases during an irradiation leading to decrease in the efficacy of the photosensitization reaction against the target cell in vitro. OBJECTIVE: The aim of this study was to obtain solutions with high dissolved oxygen levels in cultivated wells with perceiving oxygen environment and photosensitizer bleaching for photosensitization reaction studies. MATERIALS AND METHODS: We used a 10-mm-wide optical cell cuvette with a 1-mm optical path length as the well...
October 27, 2017: Photomedicine and Laser Surgery
https://www.readbyqxmd.com/read/29071034/alterations-in-auditory-electrophysiological-responses-associated-with-temporary-suppression-of-tinnitus-induced-by-low-level-laser-therapy-a-before-after-case-series
#6
Katayoon Montazeri, Saeid Mahmoudian, Zahra Razaghi, Mohammad Farhadi
Introduction: Tinnitus is the phantom auditory perception of sound in the absence of an external or internal acoustic stimulus. The treatment is difficult due to multiple etiologies and great psychological influence. The purpose of this study was to determine alterations in auditory physiological and electrophysiological responses associated with temporary suppression of tinnitus induced by low-level laser (LLL) irradiation. Methods: This study was conducted on 20 subjects with subjective tinnitus. All subjects signed the informed consent form and satisfied all the study eligibility criteria...
2017: Journal of Lasers in Medical Sciences
https://www.readbyqxmd.com/read/29071032/comparative-effectiveness-of-low-level-laser-therapy-and-transcutaneous-electric-nerve-stimulation-on-temporomandibular-joint-disorders
#7
Massoud Seifi, Asghar Ebadifar, Sattar Kabiri, Mohammad Reza Badiee, Zahra Abdolazimi, Parisa Amdjadi
Introduction: Temporomandibular joint disorders (TMDs) are the most common source of pain on the face. There are multiple etiologies, and several types of treatment have been reported. The use of non-invasive and reversible therapies in the treatment of such problems is recommended. The present study evaluated the effect of low-level laser (LLL) therapy and transcutaneous electric nerve stimulation (TENS) on TMDs. Methods: In this single-blind study, 40 patients with temporomandibular disorders were randomly divided into four groups: TENS (TENSTem dental), LLL (diode 810 nm CW), shamTENS, and sham-LLL...
2017: Journal of Lasers in Medical Sciences
https://www.readbyqxmd.com/read/29048054/coherent-laser-phase-retrieval-in-the-presence-of-measurement-imperfections-and-incoherent-light
#8
Anders K Hansen
Phase retrieval is a powerful numerical method that can be used to determine the wavefront of laser beams based only on intensity measurements, without the use of expensive, low-resolution specialized wavefront sensors such as Shack-Hartmann sensors. However, phase retrieval techniques generally suffer from poor convergence and fidelity when the input measurements contain electronic or optical noise and/or an incoherent intensity contribution overlapped with the otherwise spatially coherent laser beam. Here, we present an implementation of a modified version of the standard multiple-plane Gerchberg-Saxton algorithm and demonstrate that it is highly successful at extracting the intensity profile and wavefront of the spatially coherent part of the light from various lasers, including tapered laser diodes, at a very high fidelity despite the presence of incoherent light and noise...
September 10, 2017: Applied Optics
https://www.readbyqxmd.com/read/29041690/critical-side-channel-effects-in-random-bit-generation-with-multiple-semiconductor-lasers-in-a-polarization-based-quantum-key-distribution-system
#9
Heasin Ko, Byung-Seok Choi, Joong-Seon Choe, Kap-Joong Kim, Jong-Hoi Kim, Chun Ju Youn
Most polarization-based BB84 quantum key distribution (QKD) systems utilize multiple lasers to generate one of four polarization quantum states randomly. However, random bit generation with multiple lasers can potentially open critical side channels that significantly endangers the security of QKD systems. In this paper, we show unnoticed side channels of temporal disparity and intensity fluctuation, which possibly exist in the operation of multiple semiconductor laser diodes. Experimental results show that the side channels can enormously degrade security performance of QKD systems...
August 21, 2017: Optics Express
https://www.readbyqxmd.com/read/28986966/vertical-cavity-surface-emitting-laser-sources-for-gigahertz-bandwidth-multiwavelength-frequency-domain-photon-migration
#10
Thomas D O'Sullivan, Keunsik No, Alex Matlock, Robert V Warren, Brian Hill, Albert E Cerussi, Bruce J Tromberg
Frequency-domain photon migration (FDPM) uses modulated laser light to measure the bulk optical properties of turbid media and is increasingly applied for noninvasive functional medical imaging in the near-infrared. Although semiconductor edge-emitting laser diodes have been traditionally used as miniature light sources for this application, we show that vertical-cavity surface-emitting lasers (VCSELs) exhibit output power and modulation performance characteristics suitable for FDPM measurements of tissue optical properties at modulation frequencies exceeding 1 GHz...
October 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/28967084/the-effect-of-ultrasonically-activated-irrigation-and-laser-based-root-canal-irrigation-methods-on-debris-removal
#11
Aysenur Kamaci, Berdan Aydin, Necdet Erdilek
PURPOSE: To test the efficacy of debris removal of 5 in vitro irrigation protocols: conventional irrigation, irrigation activated by ultrasound, Er:YAG laser with photon-induced photoacoustic streaming (PIPS) tip, and 2 diode laser techniques. METHODS: The root canals of 75 extracted human canine teeth were enlarged and bisected longitudinally. Standardized grooves were prepared 2-6 mm from the root apex and filled with 0.5 mm of dentine debris. The teeth were reassembled and irrigated using 1 of the following techniques (n = 15/technique): (1) conventional irrigation, (2) diode laser irrigation - tip placed 2 mm from working length, (3) diode laser irrigation - tip placed at root canal orifice, (4) Er:YAG laser - PIPS, and (5) ultrasonically activated irrigation...
September 22, 2017: International Journal of Artificial Organs
https://www.readbyqxmd.com/read/28887223/efficacy-of-erythrosine-and-cyanidin-3-glucoside-mediated-photodynamic-therapy-on-porphyromonas-gingivalis-biofilms-using-green-light-laser
#12
Aroon Teerakapong, Teerasak Damrongrungruang, Sajee Sattayut, Noppawan Phumala Morales, Surada Tantananugool
BACKGROUND: The purpose of this in vitro study was to evaluate the efficacy of erythrosine and cyanidin-3-glucoside as photosensitizers in PDT for the elimination of Porphyromonas gingivalis (P. gingivalis) biofilms. METHODS: P. gingivalis biofilms were prepared from a chronic periodontitis subject. Erythrosine and cyanidin-3-glucoside were prepared and randomly allocated as follows: 110, 220, 330, and 440μM erythrosine; 101, 202, 303, and 404μM anthocyanin; and 440μM erythrosine+404μM cyanidin-3-glucoside...
September 5, 2017: Photodiagnosis and Photodynamic Therapy
https://www.readbyqxmd.com/read/28856042/fluorescence-depth-estimation-from-wide-field-optical-imaging-data-for-guiding-brain-tumor-resection-a-multi-inclusion-phantom-study
#13
Dennis Wirth, Kolbein Kolste, Stephen Kanick, David W Roberts, Frédéric Leblond, Keith D Paulsen
Studies have shown that fluorescent agents demarcate tumor from surrounding brain tissue and offer intraoperative guidance during resection. However, visualization of fluorescence signal from tumor below the surgical surface or through the appearance of blood in the surgical field is challenging. We have previously described red light imaging techniques for estimating fluorescent depths in turbid media. In this study, we evaluate these methods over a broader range of fluorophore concentrations, and investigate the ability to resolve multiple fluorescent emissions in the same plane or at different depths along the axis of imaging...
August 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28845670/unveiling-structurally-engineered-carrier-dynamics-in-hybrid-quasi-two-dimensional-perovskite-thin-films-toward-controllable-emission
#14
Qiuyu Shang, Yunuan Wang, Yangguang Zhong, Yang Mi, Liang Qin, Yuefeng Zhao, Xiaohui Qiu, Xinfeng Liu, Qing Zhang
Quasi-two-dimensional Ruddlesden-Popper perovskites driving carrier self-separation have rapidly advanced the development of high-performance optoelectronic devices. However, insightful understanding of carrier dynamics in the perovskites is still inadequate. The distribution of multiple perovskite phases, crucial for carrier separation, is controversial. Here we report a systematic study on carrier dynamics of spin-coated (C6H5CH2CH2NH3)2(CH3NH3)n-1PbnI3n+1 (n = 3 and 5) perovskite thin films. Efficient electrons transfer from small-n to large-n perovskite phases, and holes transfer reversely with time scales from ∼0...
September 5, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28823025/nanomedicine-associated-with-photodynamic-therapy-for-glioblastoma-treatment
#15
REVIEW
Leonardo B de Paula, Fernando L Primo, Antonio C Tedesco
Glioblastoma, also known as glioblastoma multiforme (GBM), is the most recurrent and malignant astrocytic glioma found in adults. Biologically, GBMs are highly aggressive tumors that often show diffuse infiltration of the brain parenchyma, making complete surgical resection difficult. GBM is not curable with surgery alone because tumor cells typically invade the surrounding brain, rendering complete resection unsafe. Consequently, present-day therapy for malignant glioma remains a great challenge. The location of the invasive tumor cells presents several barriers to therapeutic delivery...
October 2017: Biophysical Reviews
https://www.readbyqxmd.com/read/28741866/a-review-of-available-laser-and-intense-light-source-home-devices-a-dermatologist-s-perspective
#16
REVIEW
Margit Lw Juhász, Melissa K Levin, Ellen S Marmur
BACKGROUND: Home optical devices are becoming an increasingly popular treatment modality sought out by patients for dermatologic pathologies such as acne, hair removal and anti-aging, as these devices are a low-cost and convenient therapy choice. METHODS: An Internet search using PubMed.gov was completed with search terms, "home device dermatology," "home device acne," "home device hair" or "hair removal," and "home device aging." RESULTS: Currently, there are multiple home optical devices available on the market...
July 25, 2017: Journal of Cosmetic Dermatology
https://www.readbyqxmd.com/read/28735174/tetherless-near-infrared-control-of-brain-activity-in-behaving-animals-using-fully-implantable-upconversion-microdevices
#17
Ying Wang, Xudong Lin, Xi Chen, Xian Chen, Zhen Xu, Wenchong Zhang, Qinghai Liao, Xin Duan, Xin Wang, Ming Liu, Feng Wang, Jufang He, Peng Shi
Many nanomaterials can be used as sensors or transducers in biomedical research and they form the essential components of transformative novel biotechnologies. In this study, we present an all-optical method for tetherless remote control of neural activity using fully implantable micro-devices based on upconversion technology. Upconversion nanoparticles (UCNPs) were used as transducers to convert near-infrared (NIR) energy to visible light in order to stimulate neurons expressing different opsin proteins. In our setup, UCNPs were packaged in a glass micro-optrode to form an implantable device with superb long-term biocompatibility...
October 2017: Biomaterials
https://www.readbyqxmd.com/read/28669429/hybrid-photoacoustic-ultrasound-tomograph-for-real-time-finger-imaging
#18
Milan Oeri, Wolfgang Bost, Nicolas Sénégond, Steffen Tretbar, Marc Fournelle
We report a target-enclosing, hybrid tomograph with a total of 768 elements based on capacitive micromachined ultrasound transducer technology and providing fast, high-resolution 2-D/3-D photoacoustic and ultrasound tomography tailored to finger imaging. A freely programmable ultrasound beamforming platform sampling data at 80 MHz was developed to realize plane wave transmission under multiple angles. A multiplexing unit enables the connection and control of a large number of elements. Fast image reconstruction is provided by GPU processing...
June 29, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28607639/effect-of-diode-laser-irradiation-on-compressive-strength-of-dental-amalgam
#19
Mitra Tabari, Reza Fekrazad, Homayoun Alaghemand, Mahtab Hamzeh
INTRODUCTION: One of the biggest disadvantages of dental amalgam is that gaining its ultimate strength is a slow process. The use of a rapid-setting amalgam with high early compressive strength could be a better option in preventing early fractures in pediatric dentistry. The aim of this study was to determine the effect of diode laser irradiation on compressive strength of dental amalgam. METHODS: A case-control study was performed on 180 amalgam samples made at the Tehran Dental Material Research Center in 2014...
April 2017: Electronic Physician
https://www.readbyqxmd.com/read/28580938/harnessing-speckle-for-a-sub-femtometre-resolved-broadband-wavemeter-and-laser-stabilization
#20
Nikolaus Klaus Metzger, Roman Spesyvtsev, Graham D Bruce, Bill Miller, Gareth T Maker, Graeme Malcolm, Michael Mazilu, Kishan Dholakia
The accurate determination and control of the wavelength of light is fundamental to many fields of science. Speckle patterns resulting from the interference of multiple reflections in disordered media are well-known to scramble the information content of light by complex but linear processes. However, these patterns are, in fact, exceptionally rich in information about the illuminating source. We use a fibre-coupled integrating sphere to generate wavelength-dependent speckle patterns, in combination with algorithms based on the transmission matrix method and principal component analysis, to realize a broadband and sensitive wavemeter...
June 5, 2017: Nature Communications
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