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Infrared laser

Qian Zhao, Yunhong Liang, Lei Ren, Feng Qiu, Zhihui Zhang, Luquan Ren
A hydrogel material system which was fit for molding and 3D printing was developed to fabricate bilayer hydrogel actuators with controllable temperature and near infrared laser responses. Polymerization on interface boundary of layered structure enhanced the bonding strength of hydrogel actuators. By utilizing anisotropic of microstructure along with thickness direction, bilayer hydrogel actuators fabricated via molding realized intelligent bending/shrinking responses, which guided the preparation of hydrogel ink for 3D printing...
December 2, 2017: Journal of the Mechanical Behavior of Biomedical Materials
Eric J Stanton, Nicolas Volet, John E Bowers
A resonator is characterized with two cascaded arrayed waveguide gratings (AWGs) in a ring formation. From this structure, the on-chip transmittance of a single AWG is extracted, independent of coupling efficiency. It provides improved measurement accuracy, which is essential for developing AWGs with extremely low loss. Previous methods normalize the off-chip AWG transmittance to that of a reference waveguide with identical coupling, leading to an uncertainty of ∼14 % on the extracted on-chip AWG transmittance...
November 27, 2017: Optics Express
Gayathri Bharathan, Robert I Woodward, Martin Ams, Darren D Hudson, Stuart D Jackson, Alex Fuerbach
We report the development of a widely tunable all-fiber mid-infrared laser system based on a mechanically robust fiber Bragg grating (FBG) which was inscribed through the polymer coating of a Ho3+-Pr3+ co-doped double clad ZBLAN fluoride fiber by focusing femtosecond laser pulses into the core of the fiber without the use of a phase mask. By applying mechanical tension and compression to the FBG while pumping the fiber with an 1150 nm laser diode, a continuous wave (CW) all-fiber laser with a tuning range of 37 nm, centered at 2870 nm, was demonstrated with up to 0...
November 27, 2017: Optics Express
B Mirzaei, J R G Silva, D Hayton, C Groppi, T Y Kao, Q Hu, J L Reno, J R Gao
We present an 8-beam local oscillator (LO) for the astronomically significant [OI] line at 4.7 THz. The beams are generated using a quantum cascade laser (QCL) in combination with a Fourier phase grating. The grating is fully characterized using a third order distributed feedback (DFB) QCL with a single mode emission at 4.7 THz as the input. The measured diffraction efficiency of 74.3% is in an excellent agreement with the calculated result of 75.4% using a 3D simulation. We show that the power distribution among the diffracted beams is uniform enough for pumping an array receiver...
November 27, 2017: Optics Express
Hong Chen, Pei-Fei Liu, Bing-Xuan Li, Hua Lin, Li-Ming Wu, Xin-Tao Wu
New middle and far-infrared (MFIR) nonlinear optical (NLO) chalcogenides have been receiving increasing attention for their great importance in military and civil fields. In addition, the current challenge in the efforts for identifying a promising MFIR NLO material lies in achieving simultaneously large second-harmonic generation (SHG) intensity and high laser-induced damage threshold (LIDT) in the same material. In this study, two quaternary non-centrosymmetric (NCS) sulfides, BaAg2GeS4 (1) and BaAg2SnS4 (2), were synthesized from a high-temperature solid-state reaction using BaCl2 flux in evacuated closed silica tubes...
December 8, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Venkata Siva Gummaluri, Radhika V Nair, S R Krishnan, C Vijayan
In this Letter, we report on the design, fabrication, and implementation of a novel plasmon-mode-driven low-threshold near-infrared (NIR) random laser (RL) in the 850-900 nm range based on plasmonic ZnS@Au core-shell scatterers. Plasmon modes in the NIR region are used for nanoscale scatterer engineering of ZnS@Au core-shell particles to enhance scattering, as against pristine ZnS. This plasmonic scattering enhancement coupled with femtosecond (fs) laser pumping is shown to cause a three-fold lasing threshold reduction from 325  μJ/cm2 to 100  μJ/cm2 and a mode Q-factor enhancement from 200 to 540 for ZnS@Au-based RL, as compared to pristine ZnS-based RL...
December 1, 2017: Optics Letters
R I Woodward, D D Hudson, A Fuerbach, S D Jackson
We propose and demonstrate a simple route to few-optical-cycle pulse generation from a mid-infrared fiber laser through nonlinear compression of pulses from a holmium-doped fiber oscillator using a short length of chalcogenide fiber and a grating pair. Pulses from the oscillator with 265-fs duration at 2.86 μm are spectrally broadened through self-phase modulation in step-index As2S3 fiber to 141-nm bandwidth and then re-compressed to 70 fs (7.3 optical cycles). These are the shortest pulses from a mid-infrared fiber system to date, and we note that our system is compact, robust, and uses only commercially available components...
December 1, 2017: Optics Letters
Feng Liu, Laurent Gallais
We evaluate and apply lock-in thermography as a method to quantitatively evaluate absorption losses of optical coatings. The principle of the method consists of applying periodically modulated laser intensity on the coatings and to monitor the periodic surface temperature evolution with an infrared camera. By application of a lock-in correlation procedure and using calibrated absorption samples, it is possible to obtain quantitative absorption values and to obtain absorption mappings with spatial resolution that depends on the optical configuration...
November 20, 2017: Applied Optics
Chenquan Ni, Weiqing Gao, Xiangcai Chen, Li Chen, Yong Zhou, Wei Zhang, Jigang Hu, Meisong Liao, Takenobu Suzuki, Yasutake Ohishi
A numerical simulation of third-order cascaded Raman fiber laser based on tellurite fiber at the 2-5 μm waveband is presented. The Raman fiber laser can be optimized with the most suitable tellurite fiber length of 0.5-1.0 m and the most reasonable reflectivity of the third-order Stokes output FBG32 of 10%-20%. We demonstrate numerically that the third-order Stokes wave can reach the maximum average power of 45.2 W and the maximum optical conversion efficiency of 45.2%, corresponding to the FBG32 reflectivity of 10% and the tellurite fiber length of 0...
November 20, 2017: Applied Optics
Yue Qiao, Fei Ma, Chao Liu, Bo Zhou, Qiaolin Wei, Wanlin Li, Danni Zhong, Yangyang Li, Min Zhou
With the ever-growing threat of bacterial infections, especially for multidrug-resistant microbial infections, the development of highly effective treatment modalities to inhibit the infections is challenging. Although silver nanoparticles have been intensively applied as an antimicrobial agent for decades, the therapeutic efficacy towards multidrug-resistant bacteria is still unsatisfactory. Here, we show that near-infrared (NIR) laser-excited silver triangular nanoparticles (Tri-Ag) can efficiently kill Gram-negative Escherichia coli (E...
December 7, 2017: ACS Applied Materials & Interfaces
Ye Wu, Xiaoming Li, Yi Wei, Yu Gu, Haibo Zeng
Photo-communication has attracted great attention because of the rapid development of wireless information transmission technology. However, it is still a great challenge in cryptography communications, where it is greatly weakened by the openness of the light channels. Here, visible-infrared dual-mode narrowband perovskite photodetectors were fabricated and a new photo-communication encryption technique was proposed. For the first time, highly narrowband and two-photon absorption (TPA) resultant photoresponses within a single photodetector are demonstrated...
December 7, 2017: Nanoscale
Sarah Hocker, Harold S Rabinovitz, Margaret Oliviero, Jane Grant-Kels, Alon Scope
Distinguishing between benign and malignant neoplasms of the skin is a daily challenge to dermatologists. With the use of a dermatoscope and other imaging devices, the diagnosis is often more precise. The confocal microscope is a device that uses a near-infrared laser to perform noninvasive imaging of the skin. The benefit is that the images immediately provide additional, cellular-level information that can assist in diagnosis. However, lesions may share overlapping characteristics on confocal microscopy, and hence, benign lesions can still display confocal features concerning for a cancerous process, justifying a biopsy...
October 2017: Dermatology Practical & Conceptual
Gianna Móes Albuquerque-Pontes, Heliodora Leão Casalechi, Shaiane Silva Tomazoni, Andrey Jorge Serra, Cheila de Sousa Bacelar Ferreira, Rodrigo Barbosa de Oliveira Brito, Brunno Lemes de Melo, Adriane Aver Vanin, Kadma Karênina Damasceno Soares Monteiro, Humberto Dellê, Lucio Frigo, Rodrigo Labat Marcos, Paulo de Tarso Camillo de Carvalho, Ernesto Cesar Pinto Leal-Junior
This study aimed to analyze the protective effects of photobiomodulation therapy (PBMT) with combination of low-level laser therapy (LLLT) and light emitting diode therapy (LEDT) on skeletal muscle tissue to delay dystrophy progression in mdx mice (DMD mdx ). To this aim, mice were randomly divided into five different experimental groups: wild type (WT), placebo-control (DMD mdx ), PBMT with doses of 1 J (DMD mdx ), 3 J (DMD mdx ), and 10 J (DMD mdx ). PBMT was performed employing a cluster probe with 9 diodes (1 x 905nm super-pulsed laser diode; 4 x 875nm infrared LEDs; and 4 x 640nm red LEDs, manufactured by Multi Radiance Medical®, Solon - OH, USA), 3 times a week for 14 weeks...
December 5, 2017: Lasers in Medical Science
Ya-Qing Bie, Gabriele Grosso, Mikkel Heuck, Marco M Furchi, Yuan Cao, Jiabao Zheng, Darius Bunandar, Efren Navarro-Moratalla, Lin Zhou, Dmitri K Efetov, Takashi Taniguchi, Kenji Watanabe, Jing Kong, Dirk Englund, Pablo Jarillo-Herrero
One of the current challenges in photonics is developing high-speed, power-efficient, chip-integrated optical communications devices to address the interconnects bottleneck in high-speed computing systems. Silicon photonics has emerged as a leading architecture, in part because of the promise that many components, such as waveguides, couplers, interferometers and modulators, could be directly integrated on silicon-based processors. However, light sources and photodetectors present ongoing challenges. Common approaches for light sources include one or few off-chip or wafer-bonded lasers based on III-V materials, but recent system architecture studies show advantages for the use of many directly modulated light sources positioned at the transmitter location...
December 2017: Nature Nanotechnology
Qixin He, Minhan Lou, Chuantao Zheng, Weilin Ye, Yiding Wang, Frank K Tittel
A Pound-Drever-Hall (PDH)-based mode-locked cavity-enhanced sensor system was developed using a distributed feedback diode laser centered at 1.53 µm as the laser source. Laser temperature scanning, bias control of the piezoelectric ceramic transducer (PZT) and proportional-integral-derivative (PID) feedback control of diode laser current were used to repetitively lock the laser modes to the cavity modes. A gas absorption spectrum was obtained by using a series of absorption data from the discrete mode-locked points...
December 2, 2017: Sensors
Valeria Califano, Francesco Bloisi, Giuseppe Perretta, Antonio Aronne, Giovanni Ausanio, Aniello Costantini, Luciano Vicari
Candida rugosa lipase (CRL) was deposited by matrix assisted pulsed laser evaporation (MAPLE) in order to immobilize the enzyme with a preserved native conformation, which ensures its catalytic functionality. For this purpose, the composition of the MAPLE target was optimized by adding the oil phase pentane to a water solution of the amino acid 3-(3,4-dihydroxyphenyl)-2-methyl-l-alanine (m-DOPA), giving a target formed by a frozen water-lipase-pentane microemulsion. Fourier transform infrared (FTIR) spectroscopy and atomic force microscopy (AFM) were used to investigate the structure of MAPLE deposited lipase films...
December 5, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Armin Lambrecht, Eric Maier, Hans-Fridtjof Pernau, Thomas Strahl, Johannes Herbst
Gas leak detection is an important issue in infrastructure monitoring and industrial production. In this context, infrared (IR) absorption spectroscopy is a major measurement method. It can be applied in an extractive or remote detection scheme. Tunable laser spectroscopy (TLS) instruments are able to detect CH₄ leaks with column densities below 10 ppm·m from a distance of 30 m in less than a second. However, leak detection of non-IR absorbing gases such as N₂ is not possible in this manner. Due to the fact that any leaking gas displaces or dilutes the surrounding background gas, an indirect detection is still possible...
December 5, 2017: Sensors
Stefany Y Holguin, Michael D Gray, Princeton Joseph, Naresh N Thadhani, Mark R Prausnitz
Exposure of carbon-black (CB) nanoparticles to near-infrared nanosecond-pulsed laser energy can cause efficient intracellular delivery of molecules by photoporation. Here, cellular bioeffects of multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs) are compared to those of CB nanoparticles. In DU145 prostate-cancer cells, photoporation using CB nanoparticles transitions from (i) cells with molecular uptake to (ii) nonviable cells to (iii) fragmented cells with increasing laser fluence, as seen previously...
December 4, 2017: Advanced Healthcare Materials
Hongyu Luo, Jianfeng Li, Chen Zhu, Xue Lai, Yongchen Hai, Yong Liu
In this report, we demonstrate mid-infrared dual-waveband (i.e., ~3 μm and ~2 μm) pulses from a cascaded gain-switched Ho3+-doped ZBLAN fiber laser by the use of hybrid pumping of 1150 nm CW and pulse LDs for the first time. Stable ~3 μm gain-switched pulses with the maximum output power 262.14 mW and shortest pulse duration of 0.824 μs were first gained at the repetition rate of 80 kHz and wavelength of 2928.5 nm. Then stable ~2 μm gain-switched pulses at 2068 nm were achieved at a switchable repetition rate between 40 kHz and 80 kHz...
December 4, 2017: Scientific Reports
Meng Yang, Yongwei Gu, Dishun Yang, Xiaomeng Tang, Jiyong Liu
BACKGROUND: This work aimed to provide useful information on the use of nanoemulsions for the percutaneous administration of triptolide. Lipid nanosystems have great potential for transdermal drug delivery. Nanoemulsions and nanoemulsion gels were prepared to enhance percutaneous permeation. Microstructure and in vitro/in vivo percutaneous delivery characteristics of triptolide (TPL)-nanoemulsions and TPL-nanoemulsion gels were compared. The integrity of the nanoemulsions and nanoemulsion gels during transdermal delivery and its effects on the surface of skin were also investigated...
December 4, 2017: Journal of Nanobiotechnology
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