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Infrared laser

Zhenhui Du, Jiaxin Wan, Jinyi Li, Gang Luo, Hong Gao, Yiwen Ma
Detection of methyl mercaptan (CH₃SH) is essential for environmental atmosphere assessment and exhaled-breath analysis. This paper presents a sensitive CH₃SH sensor based on wavelength modulation spectroscopy (WMS) with a mid-infrared distributed feedback interband cascade laser (DFB-ICL). Multicomponent spectral fitting was used not only to enhance the sensitivity of the sensor but also to determine the concentration of interferents (atmospheric water and methane). The results showed that the uncertainties in the measurement of CH₃SH, H₂O, and CH₄ were less than 1...
February 16, 2017: Sensors
A Miernik, S Hein, K Wilhelm, M Schoenthaler
Analysis of the composition of a urinary stone is one of the most important steps in the clinical management of patients with urolithiasis. Fourier transform infrared spectroscopy, X-ray diffractometry and petrographic microscopy are the techniques currently used. Novel technical developments in recent years - such as Raman spectroscopy and hyperspectral imaging - have resulted in new approaches to improve urinary stone analysis. In future, table-top portable systems may be used that allow stones to be rapidly examined directly after the operation...
February 16, 2017: Aktuelle Urologie
Zhenyu You, Yijian Sun, Dunlu Sun, Zaojie Zhu, Yan Wang, Jianfu Li, Chaoyang Tu, Jinlong Xu
We report passively Q-switched ∼2 and ∼3  μm mid-infrared (MIR) solid-state lasers with a self-assembly solvothermal-synthesized Bi<sub>2</sub>Te<sub>3</sub>/graphene heterostructure saturable absorber (SA) for the first time. Based on the oxidation resistance and high thermal conductivity of graphene, and large modulation depth of Bi<sub>2</sub>Te<sub>3</sub> nanosheets, two high-performance Q-switching lasers were realized. One is a Tm:YAP laser with a maximum average output power of 2...
February 15, 2017: Optics Letters
Huihong Lin, Ting Yu, Gongxun Bai, Qinyuan Zhang, Jianhua Hao
Near-infrared-to-near-infrared (NIR-to-NIR) anti-Stokes luminescence from Cr<sup>3+</sup> singly doped Ca<sub>3</sub>Ga<sub>2</sub>Ge<sub>3</sub>O<sub>12</sub> (CGGG) occurs under the excitation of an 808 nm diode laser. The anti-Stokes processes vary from one photon to two photon, depending on the Cr<sup>3+</sup> content (x) in Ca<sub>3</sub>Ga<sub>2-x</sub>Cr<sub>x</sub>Ge<sub>3</sub>O<sub>12</sub>...
February 15, 2017: Optics Letters
Tsuneto Kanai, Pavel Malevich, Sarayoo Sasidharan Kangaparambil, Kakuta Ishida, Makoto Mizui, Kaoru Yamanouchi, Heinar Hoogland, Ronald Holzwarth, Audrius Pugzlys, Andrius Baltuska
We report on the parametric generation of 100 fs sub-6-cycle 40 μJ pulses with the center wavelength at 5.2 μm using a 1 ps 2.1 μm pump laser and a dispersion management scheme based on bulk material. Our optically synchronized amplifier chain consists of a Ho:YAG chirped-pulse amplifier and white-light-seeded optical parametric amplifiers providing simultaneous passive carrier-envelope phase locking of three ultrashort longwave pulses at the pump, signal, and idler wavelengths corresponding, respectively, to 2...
February 15, 2017: Optics Letters
Rui Wang, Zining Yang, Hongyan Wang, Xiaojun Xu
We measured active zone temperature rise of an operational diode-pumped rubidium laser non-perturbatively with methane-based near-infrared tunable diode laser spectroscopy (TDLAS). For a Rb+ methane diode-pumped alkali laser (DPAL), the temperature rise was obtained. Especially, the temperature differences (∼10  K) between lasing and un-lasing cases were well identified, which demonstrated a high sensitivity of the method. To our knowledge, this is the first demonstration of extending the methane-based TDLAS method to DPAL study...
February 15, 2017: Optics Letters
Iban Amenabar, Simon Poly, Monika Goikoetxea, Wiwat Nuansing, Peter Lasch, Rainer Hillenbrand
Infrared nanospectroscopy enables novel possibilities for chemical and structural analysis of nanocomposites, biomaterials or optoelectronic devices. Here we introduce hyperspectral infrared nanoimaging based on Fourier transform infrared nanospectroscopy with a tunable bandwidth-limited laser continuum. We describe the technical implementations and present hyperspectral infrared near-field images of about 5,000 pixel, each one covering the spectral range from 1,000 to 1,900 cm(-1). To verify the technique and to demonstrate its application potential, we imaged a three-component polymer blend and a melanin granule in a human hair cross-section, and demonstrate that multivariate data analysis can be applied for extracting spatially resolved chemical information...
February 15, 2017: Nature Communications
Lester Andrews, Han-Gook Cho, K Sahan Thanthiriwatte, David A Dixon
Thorium atoms from laser ablation react with phosphine during condensation in excess argon to produce two new infrared absorptions at 1467.2 and 1436.6 cm(-1) near weak bands for ThH and ThH2, which increase on annealing to 25 and 30 K, indicating spontaneous reactions. Analogous experiments with uranium produced two similar bands at 1473.4 and 1456.7 cm(-1) above UH at 1423.8 cm(-1) and another absorption at 1388.2 cm(-1). Electronic structure calculations at the coupled cluster CCSD(T) for Th and density functional theory calculations for U as well as their proximity to other actinide hydride absorptions support assignments of these bands to the simplest molecules HP═ThH2, HP═UH2, and PH2-UH...
February 14, 2017: Inorganic Chemistry
Laura Gemini, Tim Schmitz, Rainer Kling, Stephan Barcikowski, Bilal Gökce
The distinctive feature of upconverting compounds to absorb and emit light in the near-infrared region has made upconverting nanoparticles of great interest in various application fields. Nevertheless, these colloids show highly hydrophobic behavior and therefore the use of a proper stabilizing agent is necessary in most cases. Although few chemical techniques for colloid stabilization are available, it is still difficult to achieve a fully reproducible synthesis method for stable upconverting nanoparticle colloids...
February 14, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Barbara Gregori, Leonardo Guidoni, Maria Elisa Crestoni, Pedro de Oliveira, Chantal Houée-Levin, Debora Scuderi
The gas-phase structural modifications induced by the oxidation of methionine of two peptides of reverse sequence, methionine-valine (Met-Val) and valine-methionine (Val-Met), have been studied by mass-selected infrared multiple photon dissociation (IRMPD) spectroscopy in the 800-2000 cm-1 fingerprint range at the Centre Laser Infrarouge d'Orsay (CLIO) free electron laser facility. Oxidation has been achieved by •OH radicals generated by γ-radiolysis. IRMPD spectra were interpreted by static and harmonic DFT calculations and Born-Oppenheimer molecular dynamics simulations, employed to take into account all anharmonic and finite temperature effects...
February 14, 2017: Journal of Physical Chemistry. B
Calogero Fiorica, Nicolò Mauro, Giovanna Pitarresi, Cinzia Scialabba, Fabio S Palumbo, Gaetano Giammona
Here, we reported the production of hyaluronic acid/polyaspartamide-based double-network nanogels for the potential treatment of colorectal carcinoma. Graphene oxide, thanks to the huge aromatic surface area, allows to easily load high amount of irinotecan (33.0 % w/w) and confers to the system hyperthermic properties when irradiated with a near infrared (NIR) laser beam. We demonstrate that the release of antitumor drug is influenced both by the pH of the external medium and the NIR irradiation process. In vitro biological studies, conducted on human colon cancer cells (HCT 116), revealed that nanogels are uptaken by the cancer cells and, in the presence of the antitumor drug, can produce a synergistic hyperthermic/cytotoxic effect...
February 13, 2017: Biomacromolecules
Prasenjit Prasad Sukul, Kaushal Kumar
The upconversion (UC) process in lanthanide-doped nanophosphors has attracted great research interest for its extensive application potential in biological in vitro and in vivo imaging due to the high tissue penetration depth of near-infrared excitation and low autofluorescence background. In this article, the authors report the synthesis of oxide nanophosphor of size  ⩽50 nm, which forms stable aqueous dispersion. The photoluminescence study is made on the nanophosphor upon 808 and 980 nm diode laser excitations...
October 11, 2016: Methods and Applications in Fluorescence
Chaoqun You, Hongshui Wu, Mingxin Wang, Yawen Zhang, Jingwen Wang, Yanghui Luo, Lihai Zhai, Bai-Wang Sun, Xiangyang Zhang, Jin Zhu
Biodegradable polymeric nanoparticles have caused a rapidly growing interest as one of the most promising agents applied to drug delivery. Functional and core crosslinked poly (ethylene glycol) with poly (ε-caprolactone) (PEG5k-PCL10k) block copolymer and lecithin as biodegradable polymer doping polyaniline to assemble nanoparticles which were prepared at present work for targeted delivery and controlled release of cisplatin as a common anti-tumor drug. The morphology of polyaniline nanoparticles were determined by dynamic light scattering and the prepared nanoparticles show a suitable size of 83±1 nm and a uniform spherical shape...
February 13, 2017: Chemistry: a European Journal
V Grumezescu, A M Holban, L E Sima, M B Chiritoiu, G N Chiritoiu, A M Grumezescu, L Ivan, F Safciuc, F Antohe, C Florica, C R Luculescu, M C Chifiriuc, G Socol
The purpose of this study was to obtain, characterize and evaluate the cytotoxicity and antimicrobial activity of coatings based on poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) - Lysozyme (P(3HB-3HV)/Lys) and P(3HB-3HV) - Polyethylene glycol - Lysozyme (P(3HB-3HV)/PEG/Lys) spheres prepared by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique, in order to obtain functional and improved Ti-based implants. Morphological investigation of the coatings by Infrared Microscopy (IRM) and SEM revealed that the average diameter of P(3HB-3HV)/Lys spheres is around 2μm and unlike the drop cast samples, IRM recorded on MAPLE films revealed a good distribution of monitored functional groups on the entire scanned surface...
February 7, 2017: International Journal of Pharmaceutics
Dionyssios Mintzopoulos, Timothy E Gillis, Clark E Tedford, Marc J Kaufman
OBJECTIVE: Cerebral photobiomodulation (PBM) improves mood and cognition. Cerebral metabolic enhancement is a mechanism proposed to underlie PBM effects. No PBM studies to date have applied phosphorus magnetic resonance spectroscopy ((31)P MRS), which can be used to assess metabolic intermediates such as phosphocreatine (PCr) and adenosine triphosphate, the latter of which is elevated by PBM. Accordingly, we used 9.4 Tesla (31)P MRS to characterize effects of single and repeat cerebral PBM treatments on metabolism...
February 9, 2017: Photomedicine and Laser Surgery
Hui Qu, Fanchen Kong, Guanjun Wang, Mingfei Zhou
Fe-Zn and Co-Zn heteronuclear carbonyl cation complexes are produced via a laser vaporization supersonic cluster source in the gas phase. The dinuclear FeZn(CO)5+ and CoZn(CO)7+ cation complexes are observed to be the most intense heterodinuclear carbonyl cation species in the mass spectra. The infrared spectra are obtained via mass-selection and infrared photodissociation spectroscopy in the carbonyl stretching frequency region. Their geometric and electronic structures are assigned with the support of density functional calculations...
February 10, 2017: Journal of Physical Chemistry. A
Charis Beltes, Nikolaos Economides, Hercules Sakkas, Chrissanthy Papadopoulou, Theodoros Lambrianidis
OBJECTIVE: Photodynamic therapy (PDT) is considered a promising adjunct to the currently available endodontic disinfection techniques leading to more effective reduction of intracanal bacteria. The present ex vivo study aimed to assess the antimicrobial effect of PDT using indocyanine green (ICG) as photosensitizer and a near-infrared (NIR) diode laser in root canals of human teeth infected with Enterococcus faecalis. MATERIALS AND METHODS: Ninety single-rooted teeth after chemomechanical preparation and sterilization were contaminated with an E...
February 9, 2017: Photomedicine and Laser Surgery
Lin Wu, Ling Chen, Fei Liu, Xueyong Qi, Yanru Ge, Song Shen
Chemotherapy has been widely used in clinic and usually causes serious side effects. To improve therapeutic effect, it is really necessary to realize local drug release and specific therapy. In this work, we demonstrate Azo (4,4-azobis (4-cyanovaleric acid))-functionalized multifunctional nanoparticles to realize near-infrared (NIR) laser-responsive drug release and combined chemo-photothermal cancer therapy. Doxorubicin (DOX) was attached to magnetic nanoparticles via a thermal-cleavable Azo linker, which could decompose while the temperature reach ∼43°C...
January 13, 2017: Colloids and Surfaces. B, Biointerfaces
Sandra Dias, Kishan Kumawat, Shinjini Biswas, Salaru Babu Krupanidhi
Cu2SnS3 (CTS) quantum dots were synthesized by solvothermal technique with poly(vinylpyrrolidone) (PVP) as a surfactant. The structural and optical properties were studied using X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-vis spectroscopy. The electronic band gap was measured using cyclic voltammetry. The infrared photoresponse of the CTS quantum dots-incorporated device was measured under different illumination intensities of the infrared lamp, 1550 and 1064 nm lasers...
February 9, 2017: Inorganic Chemistry
Dejan Kepić, Stefania Sandoval, Ángel Pérez Del Pino, Enikö György, Laura Cabana, Belén Ballesteros, Gerard Tobias
N-doped reduced graphene oxide (RGO) has been prepared in bulk form by laser irradiation of graphene oxide (GO) dispersed in an aqueous solution of ammonia. A pulsed Nd:YAG laser with emission wavelengths in the infrared (IR) 1064 nm, visible (VIS) 532 nm, and ultraviolet (UV) 266 nm spectral regions was employed for the preparation of the N-doped RGO samples. Regardless of the laser energy employed, the resulting material presents a higher fraction of pyrrolic nitrogen compared to nitrogen atoms in pyridinic and graphitic coordination...
February 9, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
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