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Whispering-gallery Mode Lasing from Free-standing InGaN Microdisks

  • H. Choi, Yuk Cheung, Xuhui Zhang, and Yiyun Zhang
  • received 08/01/2014; accepted 08/19/2014; posted 08/26/2014; Doc. ID 220123
  • [full text: PDF (756) KB)]
  • Abstract: Multi-mode whispering-gallery mode (WGM) lasing has been observed in optically-pumped free-standing InGaN/GaN quantum well microdisks at room temperature. The ~6.6 μm optically-isolated microdisks are patterned by microsphere lithography on GaN thin-films prepared by laser lift-off of the sapphire substrate, enabling superior optical confinement. The modes are determined to be of second order according to simulations. The lasing threshold is found to be ~9.06 mJ/cm2, a quality factor Q of ~770 evaluated from the dominant mode at 430.2 nm, and a free space range (FSR) of 3.17 nm to 2.16 nm which is mode dependent.

Keywords (OCIS):

  • (140.4780) Lasers and laser optics : Optical resonators
  • (140.5960) Lasers and laser optics : Semiconductor lasers
  • (220.4000) Optical design and fabrication : Microstructure fabrication
  • (230.5750) Optical devices : Resonators
  • (140.3945) Lasers and laser optics : Microcavities

Long distance measurement-device-independent quantum key distribution with coherent-state superpositions

  • Hua Yin, Tengyun Chen, Zeng-Bing Chen, Yang Liu, Yan-Lin Tang, and We-Fei Cao
  • received 05/14/2014; accepted 08/19/2014; posted 08/20/2014; Doc. ID 212004
  • [full text: PDF (860) KB)]
  • Abstract: Measurement-device-independent quantum key distribution (MDI-QKD) is immune to all hacking strategies on the detection side. The decoy-state method is required in the protocol to protect the source from the photon- number-splitting attack. The performance of MDI-QKD with the weak coherent states (WCS) is well studied in recent works. Here in this letter, we propose to use coherent-state superpositions (CSS) in the source. Both the security transmission distance and secure key rate are improved compared with the original protocol. We use an analytical method to estimate the lower bound of yield and the upper bound of error rate, which gives two tight formulas. In our simulation, we find that the secure key rate is increased by more than one order of magnitude compared with the WCS. The protocol also shows a maximum secure distance of more than 375 km in the finite-key case with practical parameters, which is increased by more than 150 km compared with the original protocol.

Keywords (OCIS):

  • (270.5565) Quantum optics : Quantum communications
  • (270.5568) Quantum optics : Quantum cryptography
  • (270.5585) Quantum optics : Quantum information and processing

Nonlinear dynamics of Airy-Vortex 3D wave packets: Emission of vortex light waves.

  • Rodislav Driben and Torsten Meier
  • received 06/17/2014; accepted 08/19/2014; posted 08/20/2014; Doc. ID 212796
  • [full text: PDF (691) KB)]
  • Abstract: The dynamics of 3D Airy-vortex wave packets is studied under the action of strong Kerr nonlinearity. Shedding of nonlinear 3D waves out of the main wave packet with the topological charge of the emitted waves being equal to those carried by the parental light structure is demonstrated. The rapid collapse imposes a severe limitation on the propagation of multidimensional waves in Kerr media. However, the structure of the Airy beam carrier allows the coupling of light from the leading, most intense peak into neighboring peaks and consequently strongly postpones the collapse. The dependence of the critical input amplitude for the appearance of a fast collapse on the beam width is studied for wave packets with zero and non-zero topological charges. Wave packets carrying angular momentum are found to be much more resistant to the rapid collapse, especially those having small width.

Keywords (OCIS):

  • (190.3270) Nonlinear optics : Kerr effect
  • (190.5940) Nonlinear optics : Self-action effects
  • (050.4865) Diffraction and gratings : Optical vortices

Observation of dispersive wave emission by temporal cavity solitons

  • Jae Jang, Stephane Coen, Miro Erkintalo, and Stuart Murdoch
  • received 06/09/2014; accepted 08/18/2014; posted 08/20/2014; Doc. ID 213753
  • [full text: PDF (283) KB)]
  • Abstract: We examine a coherently-driven, dispersion-managed, passive Kerr fiber ring resonator and report the first direct experimental observation of dispersive wave emission by temporal cavity solitons. Our observations are in excellent agreement with analytical predictions and they are fully corroborated by numerical simulations. These results lead to a better understanding of the behavior of temporal cavity solitons under conditions where higher-order dispersion plays a significant role. Significantly, since temporal cavity solitons manifest themselves in monolithic microresonators, our results are likely to explain the origins of spectral features observed in broadband Kerr frequency combs.

Keywords (OCIS):

  • (140.4780) Lasers and laser optics : Optical resonators
  • (190.4370) Nonlinear optics : Nonlinear optics, fibers
  • (190.5530) Nonlinear optics : Pulse propagation and temporal solitons

High-sensitivity strain sensor based on inflated long period fiber grating

  • Yiping Wang, Xiaoyong Zhong, Junle Qu, Changrui Liao, Shen Liu, Jian Tang, Qiao Wang, Jing Zhao, Kaiming Yang, and Zhengyong Li
  • received 07/11/2014; accepted 08/18/2014; posted 08/19/2014; Doc. ID 216723
  • [full text: PDF (1117) KB)]
  • Abstract: We demonstrated a high-sensitivity strain sensor based on an inflated long period fiber grating (I-LPFG). The I-LPFG was inscribed, for the first time, by use of the pressure-assisted CO2 laser beam scanning technique to inflate periodically air holes of a photonic crystal fiber (PCF). Such periodic inflations enhanced the sensitivity of the LPFG-based strain sensor to -5.62 pm/μԑ. After high temperature annealing the I-LPFG, moreover, a good repeatability and stability of temperature response with a sensitivity of 11.92 pm/ ˚C was achieved.

Keywords (OCIS):

  • (050.2770) Diffraction and gratings : Gratings
  • (060.2340) Fiber optics and optical communications : Fiber optics components
  • (060.2370) Fiber optics and optical communications : Fiber optics sensors
  • (060.5295) Fiber optics and optical communications : Photonic crystal fibers

Simultaneous dual-wavelength stimulated Raman scattering in Ba(MoO4)x(WO4)1-x solid solution single crystals

  • Andrei Lebedev, Boris Ignatyev, Vladislav Isaev, and Pavel Plautskiy
  • received 07/04/2014; accepted 08/18/2014; posted 08/20/2014; Doc. ID 215249
  • [full text: PDF (488) KB)]
  • Abstract: The simultaneous dual-wavelength SRS of the same order Stokes with 532 nm nanosecond laser pulse excitation was found for the first time in Ba(MoO4)x(WO4)1-x single crystals. Results of studies of some peculiarities of this phenomenon were reported.

Keywords (OCIS):

  • (140.3380) Lasers and laser optics : Laser materials
  • (140.3550) Lasers and laser optics : Lasers, Raman
  • (140.3580) Lasers and laser optics : Lasers, solid-state
  • (190.4400) Nonlinear optics : Nonlinear optics, materials
  • (190.5650) Nonlinear optics : Raman effect

A rapid method for fabricating polymeric biconvex parabolic lenslets

  • Lei Li, Rongrong Sun, and Yang Li
  • received 05/27/2014; accepted 08/18/2014; posted 08/19/2014; Doc. ID 212888
  • [full text: PDF (1941) KB)]
  • Abstract: Micro lenslets as well as micro lens arrays have shown tremendous attractions and successes in miniature optical systems in recent decades. However, the fabrication methods for micro lenslets and micro lenslet arrays are limited. In this letter, a rapid and low-cost method for fabricating polymeric biconvex lenslets is presented. This newly developed process is simply based on wetting behavior at interface and is able to produce high quality biconvex lenslets with controllable size and shape. This technology will greatly simplify the production processes and reduce the manufacturing costs for micro optics.

Keywords (OCIS):

  • (220.0220) Optical design and fabrication : Optical design and fabrication
  • (220.3630) Optical design and fabrication : Lenses
  • (220.4000) Optical design and fabrication : Microstructure fabrication
  • (220.4610) Optical design and fabrication : Optical fabrication

Slow light microfluidics: a proposal

  • Misha Sumetsky
  • received 06/13/2014; accepted 08/18/2014; posted 08/19/2014; Doc. ID 214088
  • [full text: PDF (752) KB)]
  • Abstract: The resonant slow light structures created along a thin-walled optical capillary by nanoscale deformation of its surface can perform comprehensive simultaneous detection and manipulation of microfluidic components. This concept is illustrated with a model of a 0.5 millimeter long 5 nm high triangular bottle resonator created at a 50 micron radius silica capillary containing floating microparticles. The developed theory shows that the microparticle positions can be determined from the bottle resonator spectrum. In addition, the microparticles can be driven and simultaneously positioned at predetermined locations by the localized electromagnetic field created by the optimized superposition of eigenstates of this resonator, thus, exhibiting a multicomponent near field optical tweezers.

Keywords (OCIS):

  • (060.2340) Fiber optics and optical communications : Fiber optics components
  • (140.3945) Lasers and laser optics : Microcavities
  • (280.4788) Remote sensing and sensors : Optical sensing and sensors
  • (130.3990) Integrated optics : Micro-optical devices

Optical micro-cavity scanning 3D tomography

  • Andrea Di Donato, Luigino Criante, Sara LoTurco, and Marco Farina
  • received 06/19/2014; accepted 08/18/2014; posted 08/19/2014; Doc. ID 214303
  • [full text: PDF (1984) KB)]
  • Abstract: A scanning optical micro-cavity is exploited to achieve lens-free 3D tomography of microfluidic channels. The micro-cavity, powered by a low-coherence source, is realized by approaching a cleaved fiber to few tens of microns over the sample. The interference of scattered waves inside the cavity shapes the transverse field distribution, by focusing the beam and overcoming the diffraction limit due to the optical fiber numerical aperture. The focusing effect is preserved also in the inner layers of the sample allowing optical 3D tomography. Analysis of microfluidic channels was demonstrated thought this non-invasive technique. Although the experimental set-up recalls the well-known fiber-optic Fourier-domain common path optical coherence tomography, the proposed method has intrinsic characteristics that distinguish it from the former one

Keywords (OCIS):

  • (060.2310) Fiber optics and optical communications : Fiber optics
  • (110.4500) Imaging systems : Optical coherence tomography
  • (140.3948) Lasers and laser optics : Microcavity devices
  • (130.3990) Integrated optics : Micro-optical devices

In vivo analysis of burns in a mouse model using spectroscopic optical coherence tomography

  • Adam Wax, Volker Jaedicke, Jason Maher, manuel medina, Howard Levinson, Maria Selim, and William Brown
  • received 06/25/2014; accepted 08/18/2014; posted 08/22/2014; Doc. ID 214719
  • [full text: PDF (1219) KB)]
  • Abstract: Spectroscopic analysis of biological tissues can provide insight into changes in structure and function due to disease or injury. Depth resolved spectroscopic measurements can be implemented for tissue imaging using optical coherence tomography (OCT). Here spectroscopic OCT is applied to in vivo measurement of burn injury in a mouse model. Data processing and analysis methods are compared for their accuracy. Overall accuracy in classifying burned tissue was found to be as high as 91%, producing an area under the curve of a receiver operator characteristic curve of 0.97. The origins of the spectral changes are identified by correlation with histopathology.

Keywords (OCIS):

  • (110.4500) Imaging systems : Optical coherence tomography
  • (170.6510) Medical optics and biotechnology : Spectroscopy, tissue diagnostics

Precise control of the coupling coefficient through destructive interference in silicon waveguide Bragg gratings

  • Xu Wang, Yun Wang, jonas Flueckiger, Rick Bojko, Amy Liu, Adam Reid, James Pond, Nicolas Jaeger, and Lukas Chrostowski
  • received 05/28/2014; accepted 08/18/2014; posted 08/22/2014; Doc. ID 212993
  • [full text: PDF (2570) KB)]
  • Abstract: We present waveguide Bragg gratings with misaligned sidewall corrugations on a silicon-on-insulator platform. The grating strength can be tuned by varying the misalignment between the corrugations on the two sidewalls. This approach allows for a wide range of grating coupling coefficients to be achieved with precise control, and substantially reduces the effects of quantization error due to the finite mask grid size. The experimental results are in very good agreement with simulations using the finite-difference time-domain (FDTD) method.

Keywords (OCIS):

  • (050.2770) Diffraction and gratings : Gratings
  • (130.3120) Integrated optics : Integrated optics devices
  • (230.7370) Optical devices : Waveguides

Diffraction of orbital angular momentum carrying optical beams by a circular aperture

  • Surendra Singh, Anindya Ambuj, and Reeta Vyas
  • received 05/08/2014; accepted 08/18/2014; posted 08/20/2014; Doc. ID 211639
  • [full text: PDF (1567) KB)]
  • Abstract: Far field diffraction of Laguerre-Gauss vortex (LGV) beams of different angular momentum index by a circular aperture placed at different locations with respect to incident beam waist is studied experimentally. The experiments reveal a surprisingly simple structure for the diffraction pattern and its dependence on the orbital angular momentum index of the incident beam when the aperture is small compared to the beam radius.

Keywords (OCIS):

  • (260.0260) Physical optics : Physical optics
  • (260.1960) Physical optics : Diffraction theory
  • (140.3295) Lasers and laser optics : Laser beam characterization

Radiative effects driven by shock waves in cavity-less four-wave mixing combs

  • Matteo Conforti and Stefano Trillo
  • received 07/24/2014; accepted 08/16/2014; posted 08/26/2014; Doc. ID 217701
  • [full text: PDF (1418) KB)]
  • Abstract: We investigate the frequency comb spectrum produced in an optical fiber via multiple four-wave mixing pumped in the normal group-velocity region close to the zero-dispersion wavelength. We show that the dynamics is strongly affected by shock formation. In this regime, the resonant radiation emitted by the shock waves correctly explains the enhanced spectral peaks in the comb. The resonant frequencies found by means of perturbation theory accurately fits those observed from the numerical simulation based on the generalised nonlinear Schroedinger equation.

Keywords (OCIS):

  • (190.4370) Nonlinear optics : Nonlinear optics, fibers
  • (190.5530) Nonlinear optics : Pulse propagation and temporal solitons

Finite element based photoacoustic imaging of absolute temperature in tissue

  • Lei Yao, Hua Huang, and Huabei Jiang
  • received 05/22/2014; accepted 08/16/2014; posted 08/18/2014; Doc. ID 212008
  • [full text: PDF (494) KB)]
  • Abstract: We describe a finite element based algorithm for the reconstruction of absolute temperature distribution in tissue using photoacoustic measurements. Assuming a linear temperature dependence of the Grueneisen parameter in tissue, the algorithm aims to recover the temperature-dependent acoustic speed while a heating mechanism is used (e.g., a high power continuous-wave laser). The absolute temperature over time is then calculated using the recovered temperature-dependent acoustic speed. To validate our method, photoacoustic measurements were conducted using graphene nanosheet-containing target embedded in a 20mm-diameter tissue-like phantom with varied heating power. The results obtained suggest that quantitatively accurate temperature images can be produced, suggesting that our method may serve as a tool to guide and monitor the temperature distribution in tissue in real time non-invasively, and to improve the safety and efficacy of thermal therapy.

Keywords (OCIS):

  • (110.5120) Imaging systems : Photoacoustic imaging
  • (110.6820) Imaging systems : Thermal imaging
  • (110.6960) Imaging systems : Tomography

Steerable pencil beams for multi-Gbps indoor optical wireless communication

  • Chin Wan (Joanne) Oh, Eduward Tangdiongga, and A. Koonen
  • received 06/19/2014; accepted 08/16/2014; posted 08/18/2014; Doc. ID 214453
  • [full text: PDF (1176) KB)]
  • Abstract: We report a novel optical wireless communication system solution which supports multi-Gigabit-per-second capacity for indoors. Narrow beams, termed as pencil beams, are directed to wireless users using a tunable laser and a passive diffractive optics. This enables a wide coverage of ultra-capacity communication links to serve multiple network users simultaneously. Experimental results demonstrating data rates of up to 10 Gbps on-off-keying over a distance of more than 2.5 m are reported. Error free links beam-steered over a total wavelength range of 130 nm, with steering angle of 17.2° has been achieved. This system is proposed for short-range optical wireless communication and is promising for seamless integration in in-building optical networks.

Keywords (OCIS):

  • (050.1950) Diffraction and gratings : Diffraction gratings
  • (060.4510) Fiber optics and optical communications : Optical communications
  • (140.3600) Lasers and laser optics : Lasers, tunable
  • (060.2605) Fiber optics and optical communications : Free-space optical communication

Femtosecond pulse train shaping improves two-photon excited fluorescence measurements

  • Warren Warren, Martin Fischer, Jong Kang Park, Kimihiro Susumu, and Michael Therien
  • received 07/04/2014; accepted 08/14/2014; posted 08/19/2014; Doc. ID 215280
  • [full text: PDF (1131) KB)]
  • Abstract: Measurements of two-photon absorption (TPA) cross-sections are greatly confounded by even very weak linear absorption, for example from hot bands. In this case, the experimental power dependence of fluorescence from amplified and modelocked laser systems can differ drastically, even if the peak intensity is adjusted to be the same in both cases. A simple pulse train shaping method suppresses linear contributions and extracts the nonlinear absorption cross section, here on meso-to-meso ethyne-bridged bis[(porphinato)zinc(II)] fluorophore (DD) at 800 nm. This approach permits reliable two-photon absorption cross-section measurement even with standard modelocked lasers under conditions identical to that used for multiphoton microscopy.

Keywords (OCIS):

  • (190.4180) Nonlinear optics : Multiphoton processes
  • (190.4410) Nonlinear optics : Nonlinear optics, parametric processes
  • (190.7110) Nonlinear optics : Ultrafast nonlinear optics
  • (300.6410) Spectroscopy : Spectroscopy, multiphoton
  • (300.6420) Spectroscopy : Spectroscopy, nonlinear
  • (320.7110) Ultrafast optics : Ultrafast nonlinear optics

Iterative scalar non-paraxial algorithm for the design of Fourier phase elements

  • Giang-Nam Nguyen, Kevin Heggarty, Andreas Bacher, Peter-Jürgen Jakobs, Daniel Häringer, Philippe Gerard, Pierre Pfeiffer, and Patrick Meyrueis
  • received 07/23/2014; accepted 08/14/2014; posted 08/22/2014; Doc. ID 217628
  • [full text: PDF (1509) KB)]
  • Abstract: We propose an iterative algorithm based on our scalar non-paraxial propagator for the design of Fourier Diffractive Optical Elements (DOEs) having features on the order of the illumination wavelength. The simulation results show that our algorithm using iterative Fourier transform and iterative projection obtains higher performance DOEs than a purely scalar paraxial design with the same order of calculation time. Upon verification with the experimental results, we find that our scalar-based design method is valid for DOEs with surprisingly small feature sizes (about half the wavelength) and diffraction angles up to about 37°.

Keywords (OCIS):

  • (090.1970) Holography : Diffractive optics
  • (220.0220) Optical design and fabrication : Optical design and fabrication
  • (220.3740) Optical design and fabrication : Lithography
  • (220.4241) Optical design and fabrication : Nanostructure fabrication
  • (050.6624) Diffraction and gratings : Subwavelength structures

Quantitative phase imaging with partially coherent illumination

  • Gabriel Popescu, Christopher Edwards, Tan Nguyen, and Lynford Goddard
  • received 07/17/2014; accepted 08/14/2014; posted 08/20/2014; Doc. ID 217093
  • [full text: PDF (770) KB)]
  • Abstract: In this paper, we formulate a mathematical model for predicting experimental outcomes in quantitative phase imaging (QPI) when the illumination field is partially spatially coherent. We derive formulae that apply to QPI and discuss expected results for two classes of QPI experiments: common path and traditional interferometry, under varying degrees of spatial coherence. In particular, our results describe the physical relationship between the spatial coherence of the illuminating field and the halo effect, which is well known in phase contrast microscopy. We performed experiments relevant to this common situation and found that our theory is in excellent agreement with the data. With this new understanding of the effects of spatial coherence, our formulae offer an avenue for removing halo artifacts from phase images.

Keywords (OCIS):

  • (030.0030) Coherence and statistical optics : Coherence and statistical optics
  • (030.1640) Coherence and statistical optics : Coherence
  • (100.5070) Image processing : Phase retrieval
  • (110.0180) Imaging systems : Microscopy

Radiometric temperature measurement with Si and InGaAs single-photon avalanche photodiode

  • Sheng-Di Lin, Jau-Yang Wu, Ping-Keng Lu, and Yu-Jung Hsiao
  • received 07/24/2014; accepted 08/13/2014; posted 08/22/2014; Doc. ID 217738
  • [full text: PDF (1633) KB)]
  • Abstract: We experimentally demonstrate the use of single-photon avalanche photodiode (SPAD) for radiometric temperature measurement. The low dark count rate CMOS SPAD and a commercial InGaAs/InP SPAD can detect the themal radiation from a blackbody down to the temperatures of 510 K and 405 K, respectively. Our work shows that current SPADs are cost-effective thermal sensors for various applications.

Keywords (OCIS):

  • (120.5630) Instrumentation, measurement, and metrology : Radiometry
  • (120.6780) Instrumentation, measurement, and metrology : Temperature
  • (250.1345) Optoelectronics : Avalanche photodiodes (APDs)

Dispersive radiation induced by shock waves in passive resonators

  • Stefania Malaguti, Stefano Trillo, and Matteo Conforti
  • received 05/30/2014; accepted 08/13/2014; posted 08/19/2014; Doc. ID 213118
  • [full text: PDF (1914) KB)]
  • Abstract: We show that passive Kerr resonators pumped close to zero dispersion wavelengths on the normal dispersion side develop the resonant generation of linear waves driven by cavity (mixed dispersive-dissipative) shock waves. The resonance mechanism can be successfully described in the framework of the generalized Lugiato-Lefever equation with higher-order dispersive terms. Substantial differences with radiation from cavity solitons and purely dispersive shock waves dispersion are highlighted.

Keywords (OCIS):

  • (190.1450) Nonlinear optics : Bistability
  • (190.4370) Nonlinear optics : Nonlinear optics, fibers
  • (190.5530) Nonlinear optics : Pulse propagation and temporal solitons
  • (230.5750) Optical devices : Resonators

<< Previous Page Articles 21 to 40 of 106 Next Page >>

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