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Infrared laser

C Riek, P Sulzer, M Seeger, A S Moskalenko, G Burkard, D V Seletskiy, A Leitenstorfer
Squeezed states of electromagnetic radiation have quantum fluctuations below those of the vacuum field. They offer a unique resource for quantum information systems and precision metrology, including gravitational wave detectors, which require unprecedented sensitivity. Since the first experiments on this non-classical form of light, quantum analysis has been based on homodyning techniques and photon correlation measurements. These methods currently function in the visible to near-infrared and microwave spectral ranges...
January 18, 2017: Nature
B Bird, J Rowlette
Mid-infrared microscopy has become a key technique in the field of biomedical science and spectroscopy. This label-free, non-destructive technique permits the visualisation of a wide range of intrinsic biochemical markers in tissues, cells and biofluids by detection of the vibrational modes of the constituent molecules. Together, infrared microscopy and chemometrics is a widely accepted method that can distinguish healthy and diseased states with high accuracy. However, despite the exponential growth of the field and its research world-wide, several barriers currently exist for its full translation into the clinical sphere, namely sample throughput and data management...
January 18, 2017: Analyst
Otto Hertzberg, Alexander Bauer, Arne Küderle, Miguel A Pleitez, Werner Mäntele
An infrared spectroscopic technique is described that employs a mid-IR broadband (980-1245 cm(-1)) tunable quantum cascade laser (QCL) to produce a pump beam, and a detection method based on photothermal deflection, enhanced by total internal reflection. The IR spectra thus obtained are depth-dependent by modulating the pump beam with different frequencies between 10 Hz and 500 Hz. A model system consisting of glucose and a polymer film is used to demonstrate the depth selectivity of this technique. We also apply this photothermal depth profiling method to record in vivo IR spectra of the human epidermis at different depths...
January 18, 2017: Analyst
Anupriya Singhal, Shai Shaham
Visualizing neural-circuit assembly in vivo requires tracking growth of optically resolvable neurites. The Caenorhabditis elegans embryonic nervous system, comprising 222 neurons and 56 glia, is attractive for comprehensive studies of development; however, embryonic reporters are broadly expressed, making single-neurite tracking/manipulation challenging. We present a method, using an infrared laser, for reproducible heat-dependent gene expression in small sublineages (one to four cells) without radiation damage...
January 18, 2017: Nature Communications
Tim Oelze, Bernd Schütte, Maria Müller, Jan P Müller, Marek Wieland, Ulrike Frühling, Markus Drescher, Alaa Al-Shemmary, Torsten Golz, Nikola Stojanovic, Maria Krikunova
Irradiation of nanoscale clusters and large molecules with intense laser pulses transforms them into highly-excited non- equilibrium states. The dynamics of intense laser-cluster interaction is encoded in electron kinetic energy spectra, which contain signatures of direct photoelectron emission as well as emission of thermalized nanoplasma electrons. In this work we report on a so far not observed spectrally narrow bound state signature in the electron kinetic energy spectra from mixed Xe core - Ar shell clusters ionized by intense extreme-ultraviolet (XUV) pulses from a free-electron-laser...
January 18, 2017: Scientific Reports
Rui-Meng Yang, Chao-Ping Fu, Jin-Zhi Fang, Xiang-Dong Xu, Xin-Hua Wei, Wen-Jie Tang, Xin-Qing Jiang, Li-Ming Zhang
Theranostic nanoparticles with both imaging and therapeutic abilities are highly promising in successful diagnosis and treatment of the most devastating cancers. In this study, the dual-modal imaging and photothermal effect of hyaluronan (HA)-modified superparamagnetic iron oxide nanoparticles (HA-SPIONs), which was developed in a previous study, were investigated for CD44 HA receptor-overexpressing breast cancer in both in vitro and in vivo experiments. Heat is found to be rapidly generated by near-infrared laser range irradiation of HA-SPIONs...
2017: International Journal of Nanomedicine
Xuefeng Wang, Lester Andrews, Zongtang Fang, Kanchana Sahan Thanthiriwatte, Mingyang Chen, David A Dixon
The reactions of laser-ablated lanthanide metal atoms with hydrogen peroxide or hydrogen plus oxygen mixtures have been studied experimentally in a solid argon matrix and theoretically with the ab initio MP2 and CCSD(T) methods. The Ln(OH)3 and Ln(OH)2 molecules and Ln(OH)2(+) cations are the major products and the reactions to form those hydroxides are predicted to be highly exothermic at the CCSD(T) level. Vibronic interations are hypothesized to contribute to the abnormalities in deuterium shifts for Ln-OH(D) stretching modes for several hydroxides, consistent with CASSCF calculations...
January 17, 2017: Journal of Physical Chemistry. A
Patrick Bitter
BACKGROUND AND OBJECTIVE: A new 3-step protocol using broadband light allows patients with moderate to severe in ammatory acne to avoid potential side effects of systemic acne treatments and the risks and uncertainties associated with laser and light treatments to date. The protocol also addresses acne scarring and, with appropriate modi cations, all skin types. METHODS: The protocol consists of 6 to 8 treatments performed with a single device that allows the user to select wavelength, spot size, uence, and pulse duration...
November 1, 2016: Journal of Drugs in Dermatology: JDD
Yael Politi, Assi Levi, Moshe Lapidoth
INTRODUCTION: Acne scars are a common result of in ammatory acne, affecting many patients worldwide. Among which, atrophic scars are the most prevalent form, presenting as dermal depressions caused by inflammatory degeneration of dermal collagen. Mid-infrared laser skin interaction is characterized by its modest absorption in water and nite penetration to the mid-dermis. Since collagen is a desirable laser target, 1540-nm wavelength is amenable for collagen remodeling within the depressed area of atrophic scars...
November 1, 2016: Journal of Drugs in Dermatology: JDD
Xiaozhou Yu, Ying Qin, Qing Peng
Packaging methylammonium lead iodide perovskite (MAPbI3) based solar cells with a controlled gaseous atmosphere, such as N2 or dry air, is a promising solution for its application as outdoor photovoltaics. However, the effect of N2 and O2 on the decomposition chemistry and kinetics of MAPbI3 is not well understood yet. With in-situ Fourier transform infrared spectroscopy measurements, we show that the effective activation energy for the degradation of MAPbI3 in N2 is ~ 120 kJ/mol. The decomposition of MAPbI3 is greatly enhanced when MAPbI3 is exposed to O2...
January 16, 2017: Journal of Physical Chemistry. A
Xiangru Wang, Xiaoping Huang, Ziqiang Huang, Liang Wu, Jiyang Shang, Qi Qiu, Shuanghong Wu
We present a scheme of nonmechanical laser beam steering using ZnS/InP quantum dots doping nematic liquid crystal as the optical recording film. Because of its internal electric field generated by blue laser-induced charge carrier distribution, liquid crystal molecules are reoriented to form a phase grating which make the incident angle steer to the angle as we desire. Being a nonmechanical programmable laser beam steering, the anisotropy of the relative permittivity tensor and blue laser-induced electric carriers play a significant effect in determining the reorientable liquid crystal molecule and reconfigurable phase modulation of the gratings, that determines the steering angle and steering efficiency...
December 2017: Nanoscale Research Letters
Yi Chen, Haohuan Li, Yueyang Deng, Haifeng Sun, Xue Ke, Tianyuan Ci
: The combination of chemotherapy and photothermal therapy is a promising strategy for cancer treatment. In the present study, indocyanine green (ICG), a widely used near-infrared (NIR) dye in photothermal therapy, and chemotherapeutic drug-doxorubicin (DOX) were loaded within the nanoparticles of novel designed arylboronic ester and cholesterol modified hyaluronic acid (PPE-Chol1-HA), denoted as PCH-DI. We take advantage of reactive oxygen species (ROS) production capability of ICG and ROS-sensitivity of arylboronic ester to realize controllable drug release...
January 11, 2017: Acta Biomaterialia
Guilong Peng, Qiang He, Ying Lu, Jing Huang, Jin-Ming Lin
In this paper, a rapid and simple method using magnetic multi-walled carbon nanotubes (MWCNTS), as a solid-phase extraction (SPE) sorbent, was successfully developed for extraction and preconcentration trace amounts of Cr(III) in water samples. The synthesized magnetic-MWCNTs nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). A rhodamine derivative (R1) was synthesized and characterized as a highly selective and sensitive fluorescent derivatizing agent for Cr(III)...
February 22, 2017: Analytica Chimica Acta
Tamás Vörös, Győző György Lajgút, Gábor Magyarfalvi, György Tarczay
The [NH2, C, N, O] and the [NH2, C, N, S] molecular systems were investigated by computational and matrix-isolation spectroscopic methods. The determination of the equilibrium structures and relative energies by CCSD(T) method was followed by the computation of the harmonic and anharmonic vibrational wavenumbers, infrared intensities, relative Raman activities, and UV excitation energies. These computed data were used to assist the identification of products obtained by UV laser photolysis of 3,4-diaminofurazan and 3,4-diaminothiadiazole in low-temperature Ar and Kr matrices...
January 14, 2017: Journal of Chemical Physics
Shijiang Liu, Yangjie Li, Cheng Zhang, Liang Yang, Tingting Zhao, Ruilong Zhang, Changlong Jiang
Ratiometric fluorescence sensor exhibits advantages of sensitive response, high anti-interference ability and naked eye visualization owing to multiple independent emission peaks utilized for results analysis. To achieve such multi-emission probe, the traditional methods have involved simple mixing of two emitters or tedious synthesis processes of hybrid material. However, these probes often have problems of inconstant emission strength ratio, low light-stability, and complicated synthetic process, which limit their applications in practical field...
January 7, 2017: Journal of Colloid and Interface Science
Zhong-Mei Huang, Wei-Qi Huang, Zui-Min Jiang, Shi-Rong Liu, Xue-Ke Wu, Chao-Jian Qin
It is found that the optimum annealing temperature is about 1000°C for the infrared emission of defect states at room temperature on black silicon (BS) prepared by using a nanosecond-pulsed laser. In addition, it is observed that the suitable annealing time is 6∼8  min at 1000°C for the emission on the BS. The crystallizing proceeding in annealing on the BS can be used to explain the above annealing effect. It is interesting that the emission band becomes intensive and broader on the BS prepared in oxygen atmosphere than that prepared in vacuum in the analysis of photoluminescence spectra, where the electronic states localized at the defects from D1 to D4 doped with oxygen play an important role in the emission with the broader band which are obviously enhanced in the room temperature...
January 15, 2017: Optics Letters
Mingqi Fan, Tao Li, Guiqiu Li, Houyi Ma, Shengzhi Zhao, Kejian Yang, Christian Kränkel
The saturable absorption properties of few-layer graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>) nanosheets near 3 μm were investigated. A stable Q-switched Er:Lu<sub>2</sub>O<sub>3</sub> laser at 2.84 μm was realized by using a home-made g-C<sub>3</sub>N<sub>4</sub> saturable absorber (SA), generating a pulse duration of 351 ns and an average output power of 1.09 W at a repetition rate of 99 kHz, corresponding to a pulse energy of 11...
January 15, 2017: Optics Letters
Y Zhong, Z Goldenfeld, K Li, W Streyer, L Yu, L Nordin, N Murphy, D Wasserman
We have designed, fabricated, and characterized a guided mode resonance notch filter operating in the technologically vital mid-wave infrared (MWIR) region of the electromagnetic spectrum. The filter provides a bandstop at λ≈4.1  μm, with a 12 dB extinction on resonance. In addition, we demonstrate a high transmission background (>80%), less than 6% transmission on resonance, and an ultra-narrow bandwidth transmission notch (10  cm<sup>-1</sup>). Our filter is optically characterized using angle- and polarization-dependent Fourier transform infrared spectroscopy, and simulated using rigorous coupled-wave analysis (RCWA) with excellent agreement between simulations and our experimental results...
January 15, 2017: Optics Letters
R M Sullenberger, S M Redmond, D Crompton, A M Stolyarov, W D Herzog
We report a photothermal modulation of Mie scattering (PMMS) method that enables concurrent spatial and spectral discrimination of individual micron-sized particles. This approach provides a direct measurement of the "fingerprint" infrared absorption spectrum with the spatial resolution of visible light. Trace quantities (tens of picograms) of material were deposited onto an infrared-transparent substrate and simultaneously illuminated by a wavelength-tunable intensity-modulated quantum cascade pump laser and a continuous-wave 532 nm probe laser...
January 15, 2017: Optics Letters
Juha-Pekka Hieta, Anu Vaikkinen, Samuli Auno, Heikki Räikkönen, Markus Haapala, Gianmario Scotti, Jaakko Kopra, Petteri Piepponen, Tiina J Kauppila
In mass spectrometry imaging of tissues, the size of structures that can be distinguished is determined by the spatial resolution of the imaging technique. Here, the spatial resolution of IR laser ablation is markedly improved by increasing the distance between the laser and the focusing lens. As the distance between the laser and the lens is increased from 1 to 18 m, the ablation spot size decreases from 440 to 44 μm. This way, only the collimated center of the divergent laser beam is directed on the focusing lens, which results in better focusing of the beam...
January 11, 2017: Journal of the American Society for Mass Spectrometry
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