keyword
MENU ▼
Read by QxMD icon Read
search

Femtosecond laser

keyword
https://www.readbyqxmd.com/read/28337969/signatures-of-relativistic-spin-light-coupling-in-magneto-optical-pump-probe-experiments
#1
Ritwik Mondal, Marco Berritta, Peter Oppeneer
Femtosecond magneto-optical pump-probe measurements of ultrafast demagnetization show an intriguing difference in the first 100 fs of the magneto-optical Kerr response depending on whether the polarization of the pump and probe beams are in parallel or perpendicular configuration [Bigot {\it et al.}, Nature Phys. {\bf 5}, 515 (2009)]. Starting from a most general relativistic Hamiltonian we focus on the ultra-relativistic light-spin interaction and show that this coupling term leads to different light-induced opto-magnetic fields when pump and probe polarization are parallel and perpendicular to each other, providing thus an explanation for the measurements...
March 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28336840/spectroscopic-characterization-of-copper-chitosan-nanoantimicrobials-prepared-by-laser-ablation-synthesis-in-aqueous-solutions
#2
Maria Chiara Sportelli, Annalisa Volpe, Rosaria Anna Picca, Adriana Trapani, Claudio Palazzo, Antonio Ancona, Pietro Mario Lugarà, Giuseppe Trapani, Nicola Cioffi
Copper-chitosan (Cu-CS) nanoantimicrobials are a novel class of bioactive agents, providing enhanced and synergistic efficiency in the prevention of biocontamination in several application fields, from food packaging to biomedical. Femtosecond laser pulses were here exploited to disrupt a Cu solid target immersed into aqueous acidic solutions containing different CS concentrations. After preparation, Cu-CS colloids were obtained by tuning both Cu/CS molar ratios and laser operating conditions. As prepared Cu-CS colloids were characterized by Fourier transform infrared spectroscopy (FTIR), to study copper complexation with the biopolymer...
December 30, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335224/structural-changes-induced-in-grapevine-vitis-vinifera-l-dna-by-femtosecond-ir-laser-pulses-a-surface-enhanced-raman-spectroscopic-study
#3
Nicoleta E Dina, Cristina M Muntean, Nicolae Leopold, Alexandra Fălămaș, Adela Halmagyi, Ana Coste
In this work, surface-enhanced Raman spectra of ten genomic DNAs extracted from leaf tissues of different grapevine (Vitis vinifera L.) varieties, respectively, are analyzed in the wavenumber range 300-1800 cm(-1). Furthermore, structural changes induced in grapevine genomic nucleic acids upon femtosecond (170 fs) infrared (IR) laser pulse irradiation (λ = 1100 nm) are discussed in detail for seven genomic DNAs, respectively. Surface-enhanced Raman spectroscopy (SERS) signatures, vibrational band assignments and structural characterization of genomic DNAs are reported for each case...
May 25, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28332403/time-resolved-spectroscopic-study-of-the-defluorination-and-cyclization-reactions-of-lomefloxacin-in-water
#4
Tao Su, Ming-De Li, Jiani Ma, David Lee Phillips
The mechanism of the defluorination reaction(s) of lomefloxacin (LF) upon light illumination was investigated by using ultrafast laser flash photolysis combined with transient resonance Raman spectroscopy in near neutral water solution. The zwitterionic configuration of LF was determined to be the main species present in the near neutral water solution and was the species that was photoexcited to initiate the photochemical reaction. Femtosecond transient absorption revealed that the first excited singlet state (S1) of LF did not appreciably undergo intersystem crossing (ISC) and instead partially decayed to the ground state via fluorescence emission and partially underwent the cleavage of the carbon-fluorine bond at position 8 to produce a singlet LF aryl cation intermediate...
March 23, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28327611/biomimetic-surface-structuring-using-cylindrical-vector-femtosecond-laser-beams
#5
Evangelos Skoulas, Alexandra Manousaki, Costas Fotakis, Emmanuel Stratakis
We report on a new, single-step and scalable method to fabricate highly ordered, multi-directional and complex surface structures that mimic the unique morphological features of certain species found in nature. Biomimetic surface structuring was realized by exploiting the unique and versatile angular profile and the electric field symmetry of cylindrical vector (CV) femtosecond (fs) laser beams. It is shown that, highly controllable, periodic structures exhibiting sizes at nano-, micro- and dual- micro/nano scales can be directly written on Ni upon line and large area scanning with radial and azimuthal polarization beams...
March 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28321446/dissecting-charge-relaxation-pathways-in-cdse-cds-nanocrystals-using-femtosecond-two-dimensional-electronic-spectroscopy
#6
J W Jarrett, C Yi, T Stoll, J Rehault, A Oriana, F Branchi, G Cerullo, K L Knappenberger
Exciton relaxation dynamics of CdSe and quasi-type-II CdSe/CdS core/shell nanocrystals were examined using femtosecond two-dimensional electronic spectroscopy (2DES). The use of 2DES allowed for determination of structure-specific and state-resolved carrier dynamics for CdSe nanocrystals formed with five, or fewer, CdS passivation monolayers (ML). For CdSe and CdSe/CdS nanocrystals formed with one through three MLs of CdS, excitation using broad bandwidth femtosecond visible laser pulses generated electron-hole pairs among the |X1〉 = 2...
March 21, 2017: Nanoscale
https://www.readbyqxmd.com/read/28317683/new-technique-for-femtosecond-laser-creation-of-clear-corneal-incisions-for-cataract-surgery
#7
Sebastiano Serrao, Daniela Giannini, Domenico Schiano-Lomoriello, Giuseppe Lombardo, Marco Lombardo
PURPOSE: To evaluate the changes in corneal topography and corneal higher-order wavefront aberrations with the use of a new technique in which clear corneal incisions (CCIs) for cataract surgery are created with a femtosecond laser. SETTING: IRCCS Fondazione G.B. Bietti, Rome, Italy. DESIGN: Prospective randomized case series. METHODS: Cataract surgery patients were randomized into 2 groups. In the study group, a 3-plane CCI was created with a femtosecond laser...
January 2017: Journal of Cataract and Refractive Surgery
https://www.readbyqxmd.com/read/28317672/differences-in-energy-expenditure-for-conventional-and-femtosecond-assisted-cataract-surgery-using-2-different-phacoemulsification-systems
#8
Nilufer Yesilirmak, Vasilios F Diakonis, Adam Sise, Daniel P Waren, Sonia H Yoo, Kendall E Donaldson
PURPOSE: To compare the mean cumulative dissipated energy (CDE) in patients having femtosecond laser-assisted or conventional phacoemulsification cataract surgery using 2 different phacoemulsification platforms. SETTING: Bascom Palmer Eye Institute, Miami, Florida, USA. DESIGN: Prospective comparative nonrandomized clinical study. METHODS: Consecutive patients were scheduled to have femtosecond laser-assisted cataract surgery with the Lensx laser or conventional phacoemulsification using an active-fluidics torsional platform (Centurion) or torsional platform (Infiniti)...
January 2017: Journal of Cataract and Refractive Surgery
https://www.readbyqxmd.com/read/28316243/underwater-transparent-miniature-mechanical-hand-based-on-femtosecond-laser-induced-controllable-oil-adhesive-patterned-glass-for-oil-droplet-manipulation
#9
Jinglan Huo, Qing Yang, Feng Chen, Jiale Yong, Yao Fang, Jingzhou Zhang, Lin Liu, Xun Hou
The development of underwater superoleophobic surfaces makes researchers be swept up in boundless imagination of their applications, thereinto the oil manipulation based on such surface attracts much attention. Here, we show a simple and effective way to fabricate an underwater transparent miniature "mechanical hand" based on controllable oil-adhesive patterned glass prepared by femtosecond laser. The underwater oil-adhesive force of the patterned glasses that compose the "mechanical hand" device can be controlled from ultralow to ultrahigh through adjusting the different fraction of the untreated flat glass area to the laser-ablated rough area...
March 19, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28302635/financial-modelling-of-femtosecond-laser-assisted-cataract-surgery-within-the-national-health-service-using-a-hub-and-spoke-model-for-the-delivery-of-high-volume-cataract-surgery
#10
H W Roberts, M Z Ni, D P S O'Brart
AIMS: To develop financial models which offset additional costs associated with femtosecond laser (FL)-assisted cataract surgery (FLACS) against improvements in productivity and to determine important factors relating to its implementation into the National Health Service (NHS). METHODS: FL platforms are expensive, in initial purchase and running costs. The additional costs associated with FL technology might be offset by an increase in surgical efficiency. Using a 'hub and spoke' model to provide high-volume cataract surgery, we designed a financial model, comparing FLACS against conventional phacoemulsification surgery (CPS)...
March 16, 2017: BMJ Open
https://www.readbyqxmd.com/read/28300735/comparison-of-femtosecond-laser-assisted-descemetic-and-predescemetic-lamellar-keratoplasty-for-keratoconus
#11
Yan Lu, Ana Beatriz Diniz Grisolia, Yi-Rui Ge, Chun-Yan Xue, Qian Cao, Li-Ping Yang, Zhen-Ping Huang
PURPOSE: The purpose of this study is to compare the outcomes following femtosecond laser-assisted deep anterior lamellar keratoplasty (DALK) with 75% of stromal dissection (predescemetic group) and femtosecond laser-assisted DALK using big-bubble technique with total stromal resection (descemetic group) for the treatment of keratoconus. SUBJECTS AND METHODS: Twenty eyes of 17 patients with keratoconus were studied. There were 10 eyes of 9 patients in predescemetic group and 10 eyes of 8 patients in descemetic group...
January 2017: Indian Journal of Ophthalmology
https://www.readbyqxmd.com/read/28300169/double-flow-focused-liquid-injector-for-efficient-serial-femtosecond-crystallography
#12
Dominik Oberthuer, Juraj Knoška, Max O Wiedorn, Kenneth R Beyerlein, David A Bushnell, Elena G Kovaleva, Michael Heymann, Lars Gumprecht, Richard A Kirian, Anton Barty, Valerio Mariani, Aleksandra Tolstikova, Luigi Adriano, Salah Awel, Miriam Barthelmess, Katerina Dörner, P Lourdu Xavier, Oleksandr Yefanov, Daniel R James, Garrett Nelson, Dingjie Wang, George Calvey, Yujie Chen, Andrea Schmidt, Michael Szczepek, Stefan Frielingsdorf, Oliver Lenz, Edward Snell, Philip J Robinson, Božidar Šarler, Grega Belšak, Marjan Maček, Fabian Wilde, Andrew Aquila, Sébastien Boutet, Mengning Liang, Mark S Hunter, Patrick Scheerer, John D Lipscomb, Uwe Weierstall, Roger D Kornberg, John C H Spence, Lois Pollack, Henry N Chapman, Saša Bajt
Serial femtosecond crystallography requires reliable and efficient delivery of fresh crystals across the beam of an X-ray free-electron laser over the course of an experiment. We introduce a double-flow focusing nozzle to meet this challenge, with significantly reduced sample consumption, while improving jet stability over previous generations of nozzles. We demonstrate its use to determine the first room-temperature structure of RNA polymerase II at high resolution, revealing new structural details. Moreover, the double flow-focusing nozzles were successfully tested with three other protein samples and the first room temperature structure of an extradiol ring-cleaving dioxygenase was solved by utilizing the improved operation and characteristics of these devices...
March 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28299715/assessment-of-reproducibility-of-laser-electrospray-mass-spectrometry-using-electrospray-deposition-of-analyte
#13
Habiballah Sistani, Santosh Karki, Jieutonne J Archer, Fengjian Shi, Robert J Levis
A nonresonant, femtosecond (fs) laser is employed to desorb samples of Victoria blue deposited on stainless steel or indium tin oxide (ITO) slides using either electrospray deposition (ESD) or dried droplet deposition. The use of ESD resulted in uniform films of Victoria blue whereas the dried droplet method resulted in the formation of a ring pattern of the dye. Laser electrospray mass spectrometry (LEMS) measurements of the ESD-prepared films on either substrate were similar and revealed lower average relative standard deviations for measurements within-film (20...
March 15, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28299005/preliminary-results-of-femtosecond-laser-assisted-cataract-surgery-in-a-private-clinic-in-iran
#14
Farhad Nejat, Sara Sarahati, Sahar Mojaled Nobari, Khosrow Jadidi, Mostafa Naderi, Mohammad Amin Nejat
PURPOSE: To report the preliminary results of femtosecond laser-assisted cataract surgery in Iranian patients. METHODS: This prospective case series included 21 eyes of 21 patients with cataract. Mean patient age was 66.7 ± 10 years. The patients underwent femtosecond-laser assisted cataract surgery (VICTUS Femtosecond Laser Platform: Bausch + Lomb) and intraocular lens (IOL) implementation in Bina Eye Hospital, Tehran, Iran between May and October, 2014. Visual outcomes, intraocular pressure (IOP), and complications were evaluated three months after surgery...
January 2017: Journal of Ophthalmic & Vision Research
https://www.readbyqxmd.com/read/28295094/excess-carrier-envelope-phase-noise-generation-in-saturable-absorbers
#15
Nils Raabe, Tianli Feng, Mark Mero, Haochen Tian, Youjian Song, Wolfgang Hänsel, Ronald Holzwarth, Alexander Sell, Armin Zach, Günter Steinmeyer
Attosecond spectroscopy and precision frequency metrology depend on the stabilization of the carrier-envelope phase (CEP) of mode-locked lasers. Unfortunately, the phase of only a few types of lasers can be stabilized to jitters in the few-hundred millirad range. In a comparative experimental study, we analyze a femtosecond Ti:sapphire laser and three mode-locked fiber lasers. We numerically demodulate recorded time series of the free-running carrier-envelope beat note. Our analysis indicates a correlation between amplitude and frequency fluctuations at low Fourier frequencies for essentially all lasers investigated...
March 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28295075/femtosecond-laser-written-tm-klu-wo-sub-4-sub-sub-2-sub-waveguide-lasers
#16
Esrom Kifle, Xavier Mateos, Javier Rodríguez Vázquez de Aldana, Airan Ródenas, Pavel Loiko, Sun Yung Choi, Fabian Rotermund, Uwe Griebner, Valentin Petrov, Magdalena Aguiló, Francesc Díaz
Depressed-index channel waveguides with a circular and photonic crystal cladding structures are prepared in a bulk monoclinic Tm:KLu(WO<sub>4</sub>)<sub>2</sub> crystal by 3D direct femtosecond laser writing. The channel waveguide structures are characterized and laser operation is achieved using external mirrors. In the continuous-wave mode, the maximum output power of 46 mW is achieved at 1912 nm corresponding to a slope efficiency of 15.2% and a laser threshold of only 21 mW. Passive Q-switching of a waveguide with a circular cladding is realized using single-walled carbon nanotubes...
March 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28295072/ultra-sensitive-refractive-index-sensor-based-on-an-extremely-simple-femtosecond-laser-induced-structure
#17
Pengcheng Chen, Xuewen Shu, Hanyuan Cao, Kate Sugden
We demonstrate here an extremely simple, compact, and robust refractive index (RI) probe sensor based on a femtosecond-laser induced refractive index-modified dot (RIMD) fabricated near the end face of a single-mode fiber. The RIMD and the fiber end face form a Fabry-Perot interferometer, which is highly sensitive to surrounding RI. The fabrication process of the RIMD involves only one step and takes ∼0.1  s, which is extremely short, compared with other techniques. The proposed sensor exhibits an ultra-high sensitivity of ∼2523...
March 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28291201/-results-of-residual-ametropia-correction-using-circle-technology-after-femtosecond-laser-smile-surgery
#18
O A Kostin, S V Rebrikov, A I Ovchinnikov, A A Stepanov, Kh P Takhchidi
AIM: to evaluate functional results of reoperation performed according to the CIRCLE technology and using the VisuMax femtosecond laser and MEL-80 excimer laser in cases of regression of the refractive effect after SMILE surgery. MATERIAL AND METHODS: We studied a group of post-SMILE patients. In those, who showed regression of the refractive effect at 1 year, reoperation was performed according to the CIRCLE technology and using the VisuMax femtosecond laser. The corneal flap was separated from the stromal bed and turned aside...
2017: Vestnik Oftalmologii
https://www.readbyqxmd.com/read/28290597/femtosecond-laser-micromachining-of-compound-parabolic-concentrator-fiber-tipped-glucose-sensors
#19
Hafeez Ul Hassan, Amédée Lacraz, Kyriacos Kalli, Ole Bang
No abstract text is available yet for this article.
March 1, 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/28287573/fabrication-of-1-d-photonic-crystal-cavity-on-a-nanofiber-using-femtosecond-laser-induced-ablation
#20
Kali Prasanna Nayak, Jameesh Keloth, Kohzo Hakuta
We present a protocol for fabricating 1-D Photonic Crystal (PhC) cavities on subwavelength-diameter tapered optical fibers, optical nanofibers, using femtosecond laser-induced ablation. We show that thousands of periodic nano-craters are fabricated on an optical nanofiber by irradiating with just a single femtosecond laser pulse. For a typical sample, periodic nano-craters with a period of 350 nm and with diameter gradually varying from 50 - 250 nm over a length of 1 mm are fabricated on a nanofiber with diameter around 450 - 550 nm...
February 25, 2017: Journal of Visualized Experiments: JoVE
keyword
keyword
31972
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"