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1550 nm

Zhong-Mei Huang, Wei-Qi Huang, Tai-Ge Dong, Gang Wang, Xue-Ke Wu
It is very interesting that the enhanced peaks near 1150 and 1550 nm are observed in the photoluminescence (PL) spectra in the quantum system of Si-Ge nanolayer structure, which have the emission characteristics of a three-level system with quantum dots (QDs) pumping and emission of quasi-direct-gap band, in our experiment. In the preparing process of Si-Ge nanolayer structure by using a pulsed laser deposition method, it is discovered that the nanocrystals of Si and Ge grow in the (100) and (111) directions after annealing or electron beam irradiation...
December 2016: Nanoscale Research Letters
Alexei Smolyaninov, Mu-Han Yang, Lin Pang, Yeshaiahu Fainman
A high-density array of plasmonic coaxial nanoantennas is used to enhance the two-photon absorption (TPA) process in a conventional silicon photodetector from a mode-locked 76 MHz Ti:sapphire laser over a spectral range from 1340 to 1550 nm. This enhanced TPA was used to generate an interferometric autocorrelation trace of a 150 fs laser pulse. Unlike second-harmonic generation, this technique does not require phase matching or a bulky crystal and can be used on a low-cost integrated silicon platform over a wide range of near-IR wavelengths compatible with modern commercial tunable femtosecond sources...
October 1, 2016: Optics Letters
Sarah Qureshi, Jennifer Y Lin
Aminolevulinic acid (ALA) photodynamic therapy (PDT) is an emerging modality in the treatment of acne. While ablative fractional lasers have been used to enhance drug delivery into the epidermis, recent evidence suggests that non-ablative fractional photothermolysis may also improve uptake of ALA. We explored the use of non-ablative 1550 nm laser as a safe alternative in the delivery of ALA prior to red-light PDT for refractory inflammatory and cystic acne. Subjects referred for treatment of acne refractory to several topical and oral regimens, including isotretinoin, were pre-treated with non-ablative fractional photothermolysis (NAFP)...
October 14, 2016: Lasers in Medical Science
Jian-Hong Tang, Yan-Qin He, Jiang-Yang Shao, Zhong-Liang Gong, Yu-Wu Zhong
A star-shaped cyclometalated triruthenium complex 2(PF6)n (n = 3 and 4) with a triarylamine core was synthesized, which functions as a molecular switch with five well-separated redox states in both solution and film states. The single-crystal X-ray structure of 2(PF6)3 is presented. This complex displays four consecutive one-electron redox waves at +0.082, +0.31, +0.74, and +1.07 V vs Ag/AgCl. In each redox state, it shows significantly different NIR absorptions with λmax of 1590 nm for 2(4+), 1400 nm for 2(5+), 1060 nm for 2(6+), and 740 nm for 2(7+), respectively...
October 12, 2016: Scientific Reports
Zhichao Wu, Songnian Fu, Kai Jiang, Jue Song, Huizi Li, Ming Tang, Ping Shum, Deming Liu
We experimentally demonstrate switchable temporal soliton generation from a thulium-doped fiber laser (TDFL), using carbon nanotubes as the mode-locker. With the help of residual polarization dependent loss of a wavelength division multiplexer, a weak nonlinear polarization rotation (NPR) effect can be achieved within the laser cavity, which may provide joint contribution for passive mode-locking operation. By finely adjusting the polarization to alter the strength of NPR-based saturable absorption, the TDFL either approaches the operation regime of scalar soliton with strong NPR effect, or generates polarization rotation locked vector soliton (PRLVS) with weak NPR effect...
October 6, 2016: Scientific Reports
Xiang Guo, Chang-Ling Zou, Hojoong Jung, Hong X Tang
While the frequency conversion of photons has been realized with various approaches, the realization of strong coupling between optical modes of different colors has never been reported. Here, we present an experimental demonstration of strong coupling between telecom (1550 nm) and visible (775 nm) optical modes on an aluminum nitride photonic chip. The nonreciprocal normal-mode splitting is demonstrated as a result of the coherent interference between photons with different colors. Furthermore, a wideband, bidirectional frequency conversion with 0...
September 16, 2016: Physical Review Letters
Amr S El-Wakeel, Nazmi A Mohammed, Moustafa H Aly
In this work, a free space optical communication (FSO) link is proposed and utilized to explore and evaluate the FSO link performance under the joint occurrence of the atmospheric scattering and turbulence phenomena for 850 and 1550 nm operation. Diffraction and nondiffraction-limited systems are presented and evaluated for both wavelengths' operation, considering far-field conditions under different link distances. Bit error rate, pointing error angles, beam divergence angles, and link distance are the main performance indicators that are used to evaluate and compare the link performance under different system configurations and atmospheric phenomena combinations...
September 10, 2016: Applied Optics
Susobhan Das, Shima Fardad, Inki Kim, Junsuk Rho, Rongqing Hui, Alessandro Salandrino
As the diffraction limit is approached, device miniaturization to integrate more functionality per area becomes more and more challenging. Here we propose a strategy to increase the functionality-per-area by exploiting the modal properties of a waveguide system. With such an approach the design of a mode-multiplexed nanophotonic modulator relying on the mode-selective absorption of a patterned indium-tin-oxide (ITO) is proposed. Full-wave simulations of a device operating at the telecom wavelength of 1550 nm show that two modes can be independently modulated, while maintaining performances in line with conventional single-mode ITO modulators reported in the recent literature...
September 15, 2016: Optics Letters
Hongqiang Li, Xiangdong Ma, Danyang Yuan, Zanyun Zhang, Enbang Li, Chunxiao Tang
We propose a fiber Bragg grating (FBG) sensor interrogation system utilizing a III-V vertical cavity surface emitting laser (VCSEL) as the on-chip light source. Binary blazed grating (BBG) for coupling between III-V VCSEL and silicon-on-insulator (SOI) waveguides is demonstrated for interrogation of the FBG sensor. The footprint size of the BBG is only 5.62  μm×5.3  μm, and each BBG coupler period has two subperiods. The diameter of the VCSEL's emitting window is 5 μm, which is slightly smaller than that of the BBG coupler, to be well-matched with the proposed structure...
September 15, 2016: Optics Letters
Wei Wei, Xin Yan, Xia Zhang
A low-threshold nanolaser with all three dimensions at the subwavelength scale is proposed and investigated. The nanolaser is constructed based on an asymmetric hybrid plasmonic F-P cavity with Ag-coated end facets. Lasing characteristics are calculated using finite element method at the wavelength of 1550 nm. The results show that owing to the low modal loss, large modal confinement factor of the asymmetric plasmonic cavity structure, in conjunction with the high reflectivity of the Ag reflectors, a minimum threshold gain of 240 cm(-1) is predicted...
2016: Scientific Reports
Xiang Guo, Chang-Ling Zou, Hong X Tang
Integrated quantum photonic chips are promising for scalable, photonic based quantum information processing. Although on-chip quantum photon sources and single photon detectors have been demostrated separately, the full integration of these components on single chip is hindered by the background photons from the strong classical pump light. Here we design and fabricate an on-chip long-pass filter which can provide 70 dB attenuation for visible light near 775 nm with less than 3 dB insertion loss for light in the telecom C-band near 1550 nm...
September 5, 2016: Optics Express
Darayas N Patel, Sergey S Sarkisov, Abdalla M Darwish, John Ballato
A capillary light guide optical amplifier using nanocolloids of Yb<sup>3+</sup>-Er<sup>3+</sup> co-doped NaYF<sub>4</sub> as a filler was successfully demonstrated. A 7-cm-long and 150-micron-inner-diameter capillary light guide was capable to amplify a pulsed optical signal at 1550 nm with a gain coefficient of 0.15 cm<sup>-1</sup> at a pump power of 4 mW (980-nm wavelength). The nanocolloid gain medium was prepared by pulverizing the phosphor powder with a high-speed planetary ball mill...
September 5, 2016: Optics Express
Qiancheng Zhao, Yuewang Huang, Ozdal Boyraz
We numerically investigate the mode properties of the V-groove silicon nitride trench waveguides based on the experimental results. The trench waveguides are suitable for nonlinear applications. By manipulating the waveguide thicknesses, the waveguides can achieve zero dispersion or a maximized nonlinear parameter of 0.219  W<sup>-1</sup>·m<sup>-1</sup> at 1550 nm. Broadband four-wave mixing with a gain of 5.545  m<sup>-1</sup> is presented as an example. The waveguides can also be applied in sensing applications with an optimized evanescent intensity ratio...
September 1, 2016: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Hongxin Zhang, Tianqing Jia, Xiaoying Shang, Shian Zhang, Zhenrong Sun, Jianrong Qiu
A thorough understanding of energy transfer and upconversion (UC) processes between trivalent lanthanide (Ln(3+)) ions is essential and important for improving UC performance. However, because of the abundant energy states of Ln(3+) ions, UC mechanisms are very complicated, which makes it a challenge to exclusively verify and quantitatively evaluate the dominant process. In this study, the fundamental excitation processes of Tm(3+)-doped NaYF4 nanocrystals under 800 nm continuous wave (CW) laser excitation were experimentally investigated on the basis of the quantum transition principle...
October 7, 2016: Physical Chemistry Chemical Physics: PCCP
Ehsan Arbabi, Amir Arbabi, Seyedeh Mahsa Kamali, Yu Horie, Andrei Faraon
Metasurfaces are two-dimensional arrangements of optical scatterers rationally arranged to control optical wavefronts. Despite the significant advances made in wavefront engineering through metasurfaces, most of these devices are designed for and operate at a single wavelength. Here we show that spatial multiplexing schemes can be applied to increase the number of operation wavelengths. We use a high contrast dielectric transmittarray platform with amorphous silicon nano-posts to demonstrate polarization insensitive metasurface lenses with a numerical aperture of 0...
2016: Scientific Reports
Yu Chen, Yanzhi Wang, Linjun Wang, Meiping Zhu, Hongji Qi, Jianda Shao, Xiaojun Huang, Sheng Yang, Chao Li, Kainan Zhou, Qihua Zhu
We report on the development of near-infrared high dispersive mirrors (HDM) with a group delay dispersion (GDD) of -2000 fs<sup>2</sup>. A HDM pair based on one optimized result at two reference wavelengths (1550 nm and 1560 nm) can reduce the total oscillation of the GDD effectively in the wavelength range of 1530-1575 nm. This HDM pair is designed and fabricated in a single coating run by means of the nonuniformity in film deposition. For the first time, near-infrared HDMs with two different reference wavelengths have been successfully applied in an erbium-doped fiber chirped pulse amplification system for the compression of 4...
August 22, 2016: Optics Express
Nicholas J D Martinez, Christopher T Derose, Reinhard W Brock, Andrew L Starbuck, Andrew T Pomerene, Anthony L Lentine, Douglas C Trotter, Paul S Davids
We present experimental results for a selective epitaxially grown Ge-on-Si separate absorption and charge multiplication (SACM) integrated waveguide coupled avalanche photodiode (APD) compatible with our silicon photonics platform. Epitaxially grown Ge-on-Si waveguide-coupled linear mode avalanche photodiodes with varying lateral multiplication regions and different charge implant dimensions are fabricated and their illuminated device characteristics and high-speed performance is measured. We report a record gain-bandwidth product of 432 GHz for our highest performing waveguide-coupled avalanche photodiode operating at 1510nm...
August 22, 2016: Optics Express
Feng Qiu, Shiyoshi Yokoyama
A titanium dioxide (TiO<sub>2</sub>) / electro-optic (EO) polymer hybrid waveguide modulator was designed and fabricated. This modulator possessed a significant advantage for realizing high poling efficiency regardless of the EO polymer resistivity. The in-device EO coefficient was measured to be 100 pm/V, which was 32% higher than that of the thin polymer film. As a result, the phase modulator displayed a VπL figure of merit of 3.5 V∙cm at 1550 nm, which can be reduced further in a push-pull Mach-Zehnder interferometer structure...
August 22, 2016: Optics Express
Nan Guo, Weida Hu, Tao Jiang, Fan Gong, Wenjin Luo, Weicheng Qiu, Peng Wang, Lu Liu, Shiwei Wu, Lei Liao, Xiaoshuang Chen, Wei Lu
Graphene, a two-dimensional material, is expected to enable broad-spectrum and high-speed photodetection because of its gapless band structure, ultrafast carrier dynamics and high mobility. We demonstrate a multispectral active infrared imaging by using a graphene photodetector based on hybrid response mechanisms at room temperature. The high-quality images with optical resolutions of 418 nm, 657 nm and 877 nm and close-to-theoretical-limit Michelson contrasts of 0.997, 0.994, and 0.996 have been acquired for 565 nm, 1550 nm, and 1815 nm light imaging measurements by using an unbiased graphene photodetector, respectively...
September 21, 2016: Nanoscale
Wanjun Bi, Juanjuan Gao, Xia Li, Liangming Xiong, Meisong Liao
A mid-infrared supercontinuum (SC) light source, which has important applications in many fields, has been extensively investigated in soft glass fibers. However, the poor instinct properties of soft glass fibers and the development of ultrashort pulse lasers left an opportunity for mid-infrared SC generation in silica fiber. Until now, silica fiber has been the commonly used medium for SC generation due to its outstanding properties. In this paper, mid-infrared SC generation in short silica photonic crystal fibers (PCFs) is investigated theoretically and systematically...
August 10, 2016: Applied Optics
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