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https://www.readbyqxmd.com/read/29048054/coherent-laser-phase-retrieval-in-the-presence-of-measurement-imperfections-and-incoherent-light
#1
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
#2
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
#3
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
#4
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
#5
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
#6
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
#7
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
#8
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...
August 19, 2017: Biophysical Reviews
https://www.readbyqxmd.com/read/28741866/a-review-of-available-laser-and-intense-light-source-home-devices-a-dermatologist-s-perspective
#9
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
#10
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
#11
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
#12
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
#13
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
https://www.readbyqxmd.com/read/28512727/variability-of-high-dose-melphalan-exposure-on-oral-mucositis-in-patients-undergoing-prophylactic-low-level-laser-therapy
#14
Gustavo Henrique Rodrigues, Graziella Chagas Jaguar, Fabio Abreu Alves, Andre Guollo, Vanessa Oliveira Camandoni, Aline Santos Damascena, Vladmir Claudio Cordeiro Lima
The present study outlines the clinical impact and risk factors of oral mucositis in 79 patients with multiple myeloma following high-dose melphalan for autologous transplant. All patients underwent daily prophylactic low-level indium gallium aluminum phosphate diode laser therapy (660 nm, 15 mW, 3.75 J/cm(2), 10 s per point) from the beginning of the conditioning regimen up to day +2. Oral mucositis assessments were made daily until hospital discharge. For analysis, oral mucositis was divided into two groups according to severity: group 1, patients with oral mucositis grade <III (n = 71) and group 2, patients with oral mucositis grade ≥III (n = 8)...
July 2017: Lasers in Medical Science
https://www.readbyqxmd.com/read/28452543/phonoritonic-crystals-with-a-synthetic-magnetic-field-for-an-acoustic-diode
#15
A V Poshakinskiy, A N Poddubny
We develop a rigorous theoretical framework to describe light-sound interaction in the laser-pumped periodic multiple-quantum-well structure accounting for hybrid phonon-polariton excitations, termed phonoritons. We show that phonoritons exhibit the pumping-induced synthetic magnetic field in the artificial "coordinate-energy" space that makes transmission of left- and right- going waves different. The sound transmission nonreciprocity allows one to use such phonoritonic crystals with realistic parameters as optically controlled nanoscale acoustic diodes...
April 14, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28416848/-effect-of-low-level-laser-irradiation-on-proliferation-and-osteogenic-differentiation-of-human-adipose-derived-stromal-cells
#16
H X Sui, P J Lv, Y G Wang, Y Wang, Y C Sun
OBJECTIVE: To examine the in vitro effects of low-level laser irradiation (LLLI) on proliferation and differentiation of human adipose-derived stromal cells (hASCs). METHODS: Cultured cells were exposed to different doses of LLLI with a semiconductor diode laser (980 nm; 100 mW-12 W power output). The effects of laser on proliferation were assessed daily up to seven days of culture in cells irradiated for four consecutive days with laser doses of 2, 4, 6 or 8 J/cm(2), the cells without irradiation were used as controls...
April 18, 2017: Beijing da Xue Xue Bao. Yi Xue Ban, Journal of Peking University. Health Sciences
https://www.readbyqxmd.com/read/28401629/a-1-470%C3%A2-nm-diode-laser-in-stapedotomy-mechanical-thermal-and-acoustic-effects
#17
Simone P C Koenraads, Tjeerd de Boorder, Wilko Grolman, Digna M A Kamalski
BACKGROUND AND OBJECTIVES: Multiple laser systems have been investigated for their use in stapes surgery in patients with otosclerosis. The diode 1,470 nm laser used in this study is an attractive laser system because it is easily transported and relatively inexpensive in use. This wavelength has relative high absorption in water. This study aimed to investigate the mechanical, thermal, and acoustic effects of the diode 1,470 nm laser on a stapes in an inner ear model. MATERIALS AND METHODS: Experiments were performed in an inner ear model including fresh frozen human stapes...
April 11, 2017: Lasers in Surgery and Medicine
https://www.readbyqxmd.com/read/28374856/indium-gallium-nitride-based-ultraviolet-blue-and-green-light-emitting-diodes-functionalized-with-shallow-periodic-hole-patterns
#18
Hyun Jeong, Rafael Salas-Montiel, Gilles Lerondel, Mun Seok Jeong
In this study, we investigated the improvement in the light output power of indium gallium nitride (InGaN)-based ultraviolet (UV), blue, and green light-emitting diodes (LEDs) by fabricating shallow periodic hole patterns (PHPs) on the LED surface through laser interference lithography and inductively coupled plasma etching. Noticeably, different enhancements were observed in the light output powers of the UV, blue, and green LEDs with negligible changes in the electrical properties in the light output power versus current and current versus voltage curves...
April 4, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28362405/local-field-fluorescence-microscopy-imaging-cellular-signals-in-intact-hearts
#19
Yuriana Aguilar-Sanchez, Diego Fainstein, Rafael Mejia-Alvarez, Ariel L Escobar
In the heart, molecular signaling studies are usually performed in isolated myocytes. However, many pathological situations such as ischemia and arrhythmias can only be fully understood at the whole organ level. Here, we present the spectroscopic technique of local field fluorescence microscopy (LFFM) that allows the measurement of cellular signals in the intact heart. The technique is based on a combination of a Langendorff perfused heart and optical fibers to record fluorescent signals. LFFM has various applications in the field of cardiovascular physiology to study the heart under normal and pathological conditions...
March 8, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28301563/nicolase-an-open-source-diode-laser-combiner-fiber-launch-and-sequencing-controller-for-fluorescence-microscopy
#20
Philip R Nicovich, James Walsh, Till Böcking, Katharina Gaus
Modern fluorescence microscopy requires software-controlled illumination sources with high power across a wide range of wavelengths. Diode lasers meet the power requirements and combining multiple units into a single fiber launch expands their capability across the required spectral range. We present the NicoLase, an open-source diode laser combiner, fiber launch, and software sequence controller for fluorescence microscopy and super-resolution microscopy applications. Two configurations are described, giving four or six output wavelengths and one or two single-mode fiber outputs, with all CAD files, machinist drawings, and controller source code openly available...
2017: PloS One
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