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Articles 1 to 20 of 103 Next Page >>


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

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

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

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

Direction-sensitive transverse velocity measurement by phase-modulated structured light beams

  • Carmelo Rosales, Juan Torres, Aniceto Belmonte, and Nathaniel Hermosa
  • received 04/23/2014; accepted 08/12/2014; posted 08/13/2014; Doc. ID 210705
  • [full text: PDF (1265) KB)]
  • Abstract: The use of structured light beams to detect the velocity of targets moving perpendicularly to the beam's propagation axis opens new avenues for remote sensing of moving objects. However, determining the direction of motion is still a challenge since detection is usually done by means of an interferometric setup which only provides an absolute value of the frequency shift. Here, we put forward a novel method that addresses this issue. It uses dynamic control of the phase in the transverse plane of the structured light beam so that the direction of the particles' movement can be deduced. This is done by noting the change in the magnitude of the frequency shift as the transverse phase of the structured light is moved appropriately. We demonstrate our method with rotating micro-particles that are illuminated by a Laguerre-Gaussian beam with a rotating phase about its propagation axis. Our method, which only requires a dynamically configurable optical beam generator, can easily be used with other types of motion by appropriate engineering and dynamic modulation of the phase of the light beam.

Keywords (OCIS):

  • (140.3300) Lasers and laser optics : Laser beam shaping
  • (260.0260) Physical optics : Physical optics
  • (280.0280) Remote sensing and sensors : Remote sensing and sensors
  • (280.3340) Remote sensing and sensors : Laser Doppler velocimetry

Generation of unconventional polarization from light scattered by metallic cylinders under conical incidence.

  • Rafael Espinosa Luna, IZCOATL SAUCEDO OROZCO, and Guadalupe Lopez Morales
  • received 06/25/2014; accepted 08/12/2014; posted 08/13/2014; Doc. ID 214658
  • [full text: PDF (1168) KB)]
  • Abstract: A simple experimental method to generate unconventional polarized states from the conical scattering of light by thin metallic cylinders is presented. Results show that radial and azimuthal polarizations are easily obtained. This opens the possibility for a broad range of applications, from surgery to industrial, and even to remote sensing. To our knowledge, this is the cheaper and easier way to generate radial and azimuthal unconventional polarization states.

Keywords (OCIS):

  • (260.5430) Physical optics : Polarization
  • (290.5820) Scattering : Scattering measurements

Surface phonon polariton responses of hexagonal sapphire crystals with non-polar and semi-polar crystallographic planes

  • Sai Cheong Lee, Sha Shiong Ng, Haslan Abu Hassan, Zainuriah Hassan, and Thomas Dumelow
  • received 06/25/2014; accepted 08/11/2014; posted 08/13/2014; Doc. ID 214627
  • [full text: PDF (2501) KB)]
  • Abstract: Surface phonon polariton (SPP) characteristics of hexagonal sapphire crystals with non-polar and semi-polar crystallographic planes were investigated. A formulation that considers the effects of crystal orientation was employed to calculate the SPP dispersion curves of the samples. The SPP dispersion curves indicate that the SPP responses of sapphire crystals in non-polar and semi-polar orientations are directionally sensitive. Resonance frequencies and spectral strengths of the SPP modes can be modulated simply by tuning the angular positions of the samples. The validity of the theoretical results was confirmed by the polarized infrared attenuated total reflection measurements.

Keywords (OCIS):

  • (160.4760) Materials : Optical properties
  • (240.5420) Optics at surfaces : Polaritons
  • (240.6490) Optics at surfaces : Spectroscopy, surface
  • (260.6970) Physical optics : Total internal reflection

Adaptive Quantum State Estimation of an Entangled Qubit State

  • André Stefanov and Stefan Lerch
  • received 06/19/2014; accepted 08/11/2014; posted 08/13/2014; Doc. ID 214230
  • [full text: PDF (576) KB)]
  • Abstract: The uncertainty on the estimation of unknown parameters of a quantum state can be reduced by using adaptive measurements. Here we perform adaptive quantum state estimation of the phase in a two entangled qubits state. We experimentally demonstrate that the adaptive method outperforms non-adaptive methods.

Keywords (OCIS):

  • (190.4410) Nonlinear optics : Nonlinear optics, parametric processes
  • (270.5565) Quantum optics : Quantum communications
  • (270.5585) Quantum optics : Quantum information and processing

Sheet-scanned dual-axis confocal (SS-DAC) microscopy using Richardson-Lucy deconvolution

  • Danni Wang, Daphne Meza, Yu Wang, Liang Gao, and Jonathan Liu
  • received 06/26/2014; accepted 08/11/2014; posted 08/19/2014; Doc. ID 214815
  • [full text: PDF (7184) KB)]
  • Abstract: We have previously developed a line-scanned dual-axis confocal (LS-DAC) microscope with subcellular resolution suitable for high-frame-rate diagnostic imaging at shallow depths. Due to the loss of confocality along one dimension, the contrast (signal-to-background ratio) of a LS-DAC microscope is deteriorated compared to a point-scanned DAC microscope. However, by using a sCMOS camera for detection, a short oblique light-sheet is imaged at each scanned position. Therefore, by scanning the light sheet in only one dimension, a thin 3D volume is imaged. Both sequential two-dimensional deconvolution and three-dimensional deconvolution are performed on the thin image volume to improve the resolution and contrast of one en face confocal image section at the center of the volume, a technique we call sheet-scanned dual-axis confocal (SS-DAC) microscopy.

Keywords (OCIS):

  • (100.1830) Image processing : Deconvolution
  • (170.0180) Medical optics and biotechnology : Microscopy
  • (170.1790) Medical optics and biotechnology : Confocal microscopy
  • (170.3880) Medical optics and biotechnology : Medical and biological imaging
  • (170.5810) Medical optics and biotechnology : Scanning microscopy
  • (220.4830) Optical design and fabrication : Systems design

Terahertz Generation in Lithium Niobate Driven by Ti:Sapphire Laser Pulses and its Limitations

  • Xiaojun Wu, Sergio Carbajo, Koustuban Ravi, Frederike Ahr, Giovanni Cirmi, Yue Zhou, Oliver Muecke, and FRANZ KAERTNER
  • received 06/19/2014; accepted 08/10/2014; posted 08/13/2014; Doc. ID 214372
  • [full text: PDF (1425) KB)]
  • Abstract: We experimentally investigate the limits to 800 nm-to-terahertz (THz) energy conversion in lithium niobate at room temperature driven by amplified Ti:Sapphire laser pulses with tilted-pulse-front. The influence of the pump central wavelength, pulse duration, and fluence on THz generation is studied. We achieved a high peak efficiency of 0.12% using transform limited 150 fs pulses and observed saturation of the optical to THz conversion efficiency at a fluence of 15 mJ/cm2. We experimentally identify two main limitations for the scaling of optical-to-THz conversion efficiencies: (i) the large spectral broadening of the optical pump spectrum in combination with large angular dispersion of the tilted-pulse-front and (ii) free-carrier absorption of THz radiation due to multi-photon absorption of the 800 nm radiation.

Keywords (OCIS):

  • (140.3070) Lasers and laser optics : Infrared and far-infrared lasers
  • (320.7110) Ultrafast optics : Ultrafast nonlinear optics
  • (320.7160) Ultrafast optics : Ultrafast technology

Lasing on Tamm states in vertical cavity surface emission lasers

  • Ray-Kuang Lee, Yonan Su, Chun-Yan Lin, Ray-Ching Hong, Wen-Xing Yang, Chien-Chung Jeng, and Tien-Chang Lu
  • received 06/23/2014; accepted 08/10/2014; posted 08/13/2014; Doc. ID 214610
  • [full text: PDF (868) KB)]
  • Abstract: We report experimental observation of lasing on Tamm states, in the form of standing waves at the termination of a defect-free photonic crystal on top of vertical cavity surface emission lasers. Direct images of lasing modes at the truncated periodic potential, along one side of a square lattice, are demonstrated by collecting near-field radiation patterns, as well as in numerical simulations. Our results provide a step toward realizing surface and edge states in optical cavities.

Keywords (OCIS):

  • (240.0240) Optics at surfaces : Optics at surfaces
  • (240.6690) Optics at surfaces : Surface waves
  • (140.3948) Lasers and laser optics : Microcavity devices
  • (140.7260) Lasers and laser optics : Vertical cavity surface emitting lasers

A fifiber-chip grating coupler based on interleaved trenches with a high directionality exceeding 95%

  • Carlos Alonso Ramos, Pavel Cheben, Alejandro Ortega-Moñux, Jens Schmid, Daxia Xu, and I. Molina-Fernández
  • received 07/07/2014; accepted 08/10/2014; posted 08/13/2014; Doc. ID 216354
  • [full text: PDF (505) KB)]
  • Abstract: We propose a fifiber-chip grating coupler that interleaves the standard full and shallow etch trenches in a 220 nm thick silicon layer to provide a directionality upwards exceeding 95%. By adjusting the separation between the two sets of trenches, constructive interference is achieved in upwards direction independent of the BOX thickness and without any bottom reflectors, overlays or customized etch depths. We implement a transverse sub-wavelength structure in the fifirst two grating periods to minimize back-reflections. The grating coupler has a calculated coupling efficiency of CE -1.05 dB with a 1 dB bandwidth of 30 nm, and minimum feature size of 100 nm, compatible with deep-UV lithography.

Keywords (OCIS):

  • (050.0050) Diffraction and gratings : Diffraction and gratings
  • (130.3120) Integrated optics : Integrated optics devices
  • (230.7390) Optical devices : Waveguides, planar

Radiation tolerant Fiber Bragg Gratings for high temperature monitoring at MGy dose levels

  • Adriana Morana, Sylvain Girard, Emmanuel Marin, Claude Marcandella, Philippe Paillet, Jocelyn Périsse, Jean-Reynald Macé, Aziz Boukenter, Marco Cannas, and Youcef Ouerdane
  • received 07/14/2014; accepted 08/09/2014; posted 08/11/2014; Doc. ID 216992
  • [full text: PDF (756) KB)]
  • Abstract: We report a method for fabricating Fiber Bragg Gratings (FBG) resistant to very severe environments mixing high radiation doses (up to 3 MGy) and high temperatures (up to 230°C). Such FBGs have been written in two types of radiation resistant optical fibers (pure-silica and fluorine-doped cores) by exposures to a 800 nm femtosecond IR laser at power exceeding 500 mW and then subjected to a thermal annealing treatment of 15 minutes at 750°C. Under radiation, our study reveals that the radiation induced Bragg Wavelength Shift (BWS) at a 3 MGy dose is strongly reduced compared to responses of FBGs written with non-optimized conditions. BWS remains lower than 10 pm for temperatures of irradiation ranging from 25 to 230°C without noticeable decrease of the FBG peak amplitude. For an applicative point of view, this radiation induced BWS corresponds to an additional error on the temperature measurements lower than 1.5°C, opening the way to the development of radiation-tolerant multi-point temperature sensors for nuclear industry.

Keywords (OCIS):

  • (060.2370) Fiber optics and optical communications : Fiber optics sensors
  • (160.6030) Materials : Silica
  • (350.5610) Other areas of optics : Radiation
  • (060.3735) Fiber optics and optical communications : Fiber Bragg gratings

Tunable nonlinear double-core PT-symmetric waveguides

  • Chao Hang, Dmitry Zezyulin, Guoxiang Huang, Vladimir Konotop, and Boris Malomed
  • received 06/26/2014; accepted 08/09/2014; posted 08/11/2014; Doc. ID 213694
  • [full text: PDF (666) KB)]
  • Abstract: We propose a scheme for creating a tunable, highly nonlinear defect in a one-dimensional photonic crystal with an embedded atomic cell filled by a mixture of two isotopes of three-level atoms. The defect creates an effective double-core waveguide. The induced refractive index for a probe field can be made parity-time symmetric by means of a proper combination of a control field and a Stark field, and hence the complex defect potential obtained contains double-well real and linear imaginary parts. We also show that it is possible to form various stable nonlinear defect modes supported by the focusing nonlinearity of the system.

Keywords (OCIS):

  • (190.0190) Nonlinear optics : Nonlinear optics
  • (190.3270) Nonlinear optics : Kerr effect
  • (190.6135) Nonlinear optics : Spatial solitons

Remote two-color optical-to-optical synchronization between two passively mode-locked lasers

  • Heng Li, FRANZ KAERTNER, Alan Fry, Li-Jin Chen, Haynes Cheng, Justin May, Steve Smith, Kerstin Muehlig, Akshaya Uttamadoss, Josef Frisch, and Philip Bucksbaum
  • received 06/25/2014; accepted 08/08/2014; posted 08/08/2014; Doc. ID 214654
  • [full text: PDF (551) KB)]
  • Abstract: Utilizing balanced detection in both the radio frequency (RF) and optical domain, we remotely synchronize the repetition-rate of a Ti:sapphire oscillator to an Er-doped fiber oscillator through a 360 meter length-stabilized dispersion compensated fiber link. The drift between these two optical oscillators is 3.3 fs root mean square (rms) over 24 hours. The 68 MHz Er-doped fiber oscillator is locked to a 476 MHz local RF reference clock, and serves as a master clock to distribute 10-fs level timing signals through stabilized fiber links. This steady remote two-color optical-optical synchronization is an important step towards an integrated femtosecond fiber timing distribution system for free-electron lasers (FELs), it does not require x-ray pulses, and makes sub-10 fs optical/x-ray pump-probe experiments feasible.

Keywords (OCIS):

  • (060.2360) Fiber optics and optical communications : Fiber optics links and subsystems
  • (060.2410) Fiber optics and optical communications : Fibers, erbium
  • (140.3490) Lasers and laser optics : Lasers, distributed-feedback
  • (140.7090) Lasers and laser optics : Ultrafast lasers
  • (320.7100) Ultrafast optics : Ultrafast measurements


  • Andrey Ostrovsky, Ruben Ramos-Garcia, Victor Arrizon, Carolina Rickenstorff, and Joaquín García
  • received 06/24/2014; accepted 08/08/2014; posted 08/12/2014; Doc. ID 214557
  • [full text: PDF (854) KB)]

Keywords (OCIS):

  • (050.1970) Diffraction and gratings : Diffractive optics
  • (140.7010) Lasers and laser optics : Laser trapping
  • (050.4865) Diffraction and gratings : Optical vortices
  • (080.4865) Geometric optics : Optical vortices
  • (070.6120) Fourier optics and signal processing : Spatial light modulators

Articles 1 to 20 of 103 Next Page >>

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