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https://www.readbyqxmd.com/read/28438012/smartphone-based-dual-modality-imaging-system-for-quantitative-detection-of-color-or-fluorescent-lateral-flow-immunochromatographic-strips
#1
Yafei Hou, Kan Wang, Kun Xiao, Weijian Qin, Wenting Lu, Wei Tao, Daxiang Cui
Nowadays, lateral flow immunochromatographic assays are increasingly popular as a diagnostic tool for point-of-care (POC) test based on their simplicity, specificity, and sensitivity. Hence, quantitative detection and pluralistic popular application are urgently needed in medical examination. In this study, a smartphone-based dual-modality imaging system was developed for quantitative detection of color or fluorescent lateral flow test strips, which can be operated anywhere at any time. In this system, the white and ultra-violet (UV) light of optical device was designed, which was tunable with different strips, and the Sobel operator algorithm was used in the software, which could enhance the identification ability to recognize the test area from the background boundary information...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28438009/modulation-format-free-and-automatic-bias-control-for-optical-iq-modulators-based-on-dither-correlation-detection
#2
Xiaolei Li, Lei Deng, Xiaoman Chen, Mengfan Cheng, Songnian Fu, Ming Tang, Deming Liu
A novel automatic bias control (ABC) method for optical in-phase and quadrature (IQ) modulator is proposed and experimentally demonstrated. In the proposed method, two different low frequency sine wave dither signals are generated and added on to the I/Q bias signal respectively. Instead of power monitoring of the harmonics of the dither signal, dither-correlation detection is proposed and used to adjust the bias voltages of the optical IQ modulator. By this way, not only frequency spectral analysis isn't required but also the directional bias adjustment could be realized, resulting in the decrease of algorithm complexity and the growth of convergence rate of ABC algorithm...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28438006/measurements-and-modeling-of-multipath-interference-at-wavelengths-below-cable-cut-off-in-a-g-654-optical-fiber-span
#3
John D Downie, Jason Hurley, Hector DePedro, Steven Garner, Jeremy Blaker, Aramais Zakharian, Sergey Ten, Greg Mills
Transmission below the cable cut-off wavelength may be a concern in some systems, especially for an optical supervisory channel (OSC) operating below the signal transmission band in systems built with G.654 fiber. In this work, we constructed a cabled span of G.654-compliant fiber and measured the multipath interference (MPI) generated during propagation through the span at a range of wavelengths below the cable cut-offs of the constituent fibers. Measurements were made under a range of conditions including different splice losses and the presence or absence of higher order mode filters placed around the splices...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28438003/wavelength-multicasting-through-four-wave-mixing-with-an-optical-comb-source
#4
Hong-Fu Ting, Ke-Yao Wang, Jasper R Stroud, Keith G Petrillo, Hongcheng Sun, Amy C Foster, Mark A Foster
Based on four-wave mixing (FWM) with an optical comb source (OCS), we experimentally demonstrate 26-way or 15-way wavelength multicasting of 10-Gb/s differential phase-shift keying (DPSK) data in a highly-nonlinear fiber (HNLF) or a silicon waveguide, respectively. The OCS provides multiple spectrally equidistant pump waves leading to a multitude of FWM products after mixing with the signal. We achieve error-free operation with power penalties less than 5.7 dB for the HNLF and 4.2 dB for the silicon waveguide, respectively...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28438001/noise-reduction-in-third-order-cross-correlation-by-angle-optimization-of-the-interacting-beams
#5
V A Schanz, F Wagner, M Roth, V Bagnoud
We report on a novel technique to reduce the noise level in scanning third order cross-correlation. Large angles between the interacting beams combined with adapted crystal parameters lead to a significant decrease of noise photon generation while maintaining efficient generation of the third order signal. An enhanced scanning cross-correlator was developed based on the new technique proposed. In tests at the PHELIX laser facility this novel correlator performed within a dynamic range of 12.5 orders of magnitude...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437995/single-measurement-digital-optical-frequency-comb-based-phase-detection-brillouin-optical-time-domain-analyzer
#6
Chao Jin, Liang Wang, Yuli Chen, Nan Guo, Wenghong Chung, Hoyin Au, Zhaohui Li, Hwa-Yaw Tam, Chao Lu
A single-measurement sweep-free distributed Brillouin optical time domain analyzer (BOTDA) sensor based on phase detection is proposed and experimentally demonstrated employing digital optical frequency comb (DOFC) probe signal. Brillouin Phase Spectrum (BPS) of DOFC probe induced by Brillouin interaction is measured using coherent detection in a single acquisition, without any frequency scanning and data averaging. Single-measurement BOTDA sensor based on BPS in 10km long fiber is demonstrated with a response time of 100 μs, which is limited only by the fiber length...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437981/efficient-laser-noise-reduction-method-via-actively-stabilized-optical-delay-line
#7
Dawei Li, Cheng Qian, Ye Li, Jianye Zhao
We report a fiber laser noise reduction method by locking it to an actively stabilized optical delay line, specifically a fiber-based Mach-Zehnder interferometer with a 10 km optical fiber spool. The fiber spool is used to achieve large arm imbalance. The heterodyne signal of the two arms converts the laser noise from the optical domain to several megahertz, and it is used in laser noise reduction by a phase-locked loop. An additional phase-locked loop is induced in the system to compensate the phase noise due to environmentally induced length fluctuations of the optical fiber spool...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437980/angle-resolved-transmission-through-metal-hole-gratings
#8
F Mariani, F de León-Pérez, K J A Vendel, L Martín-Moreno, M P Van Exter
We present the first angle resolved measurements of extraordinary optical transmission (EOT) through hole array gratings in a gold film. Varying the lattice spacing of the arrays and looking at higher diffraction orders, we retrieve the angular emission pattern of the constituent holes with better signal to noise ratio than with single-hole experiments. We present a method to determine separately the angular dependence of the direct and resonant contribution to EOT by using the spectral features of the diffraction orders together with an established model...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437971/energy-efficient-on-chip-optical-diode-based-on-the-optomechanical-effect
#9
Huaqing Qiu, Jianji Dong, Li Liu, Xinliang Zhang
We propose and experimentally demonstrate an energy-efficient optical diode based on the optomechanical effect. The optical signals could transmit during forward propagation while be blocked during backward propagation. When launching optical signal with a low power of 4.0 mW, the maximum resonance red-shift of the asymmetric silicon microring resonator (MRR) could be up to 0.74 nm, in this case, a forward-backward nonreciprocal transmission ratio (NTR) of 12.7 dB has been achieved. The 10-dB and 5-dB operation bandwidths are 0...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437960/wind-ranging-and-velocimetry-with-low-peak-power-and-long-duration-modulated-laser
#10
Eiichi Yoshikawa, Tomoo Ushio
A novel approach to simultaneous wind ranging and velocimetry using low peak power, long-duration modulated laser pulse transmissions is proposed. Received signals backscattered by aerosol particles are processed by a multi-reference matched-filter (MRMF) which performs matched filter processing between the received signal and several reference signals in parallel and outputs a range-velocity profile of received power. Ranging and velocimetry are performed simultaneously by estimating received power, radial velocity, and velocity dispersion from a velocity profile at an arbitrary range in the range-velocity profile...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437959/high-average-power-2-%C3%AE-m-femtosecond-optical-parametric-oscillator-synchronously-pumped-by-a-thin-disk-mode-locked-laser
#11
T Petersen, J D Zuegel, J Bromage
A high-energy, extended-cavity femtosecond BiBO optical parametric oscillator synchronously pumped by a 1.0-ps, 1030-nm Yb:YAG, thin-disk pump laser is presented. The oscillator operated near degeneracy in a noncollinear interaction geometry, producing signal wavelength tunability from 1.99 to 2.20 μm. The signal pulses have an average power exceeding 2 W, producing 455-fs pulses at 7.08 MHz with energies up to 350 nJ, showing increased potential for tunable sources of scalable ultrafast pulses in the infrared...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437958/feed-forward-frequency-offset-estimation-for-32-qam-optical-coherent-detection
#12
Fei Xiao, Jianing Lu, Songnian Fu, Chenhui Xie, Ming Tang, Jinwen Tian, Deming Liu
Due to the non-rectangular distribution of the constellation points, traditional fast Fourier transform based frequency offset estimation (FFT-FOE) is no longer suitable for 32-QAM signal. Here, we report a modified FFT-FOE technique by selecting and digitally amplifying the inner QPSK ring of 32-QAM after the adaptive equalization, which is defined as QPSK-selection assisted FFT-FOE. Simulation results show that no FOE error occurs with a FFT size of only 512 symbols, when the signal-to-noise ratio (SNR) is above 17...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437955/cyclic-coding-for-brillouin-optical-time-domain-analyzers-using-probe-dithering
#13
Haritz Iribas, Alayn Loayssa, Florian Sauser, Miguel Llera, Sébastien Le Floch
We study the performance limits of mono-color cyclic coding applied to Brillouin optical time-domain analysis (BOTDA) sensors that use probe wave dithering. BOTDA analyzers with dithering of the probe use a dual-probe-sideband setup in which an optical frequency modulation of the probe waves along the fiber is introduced. This avoids non-local effects while keeping the Brillouin threshold at its highest level, thus preventing the spontaneous Brillouin scattering from generating noise in the deployed sensing fiber...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437950/maximum-likelihood-sequence-estimation-for-optical-complex-direct-modulation
#14
Di Che, Feng Yuan, William Shieh
Semiconductor lasers are versatile optical transmitters in nature. Through the direct modulation (DM), the intensity modulation is realized by the linear mapping between the injection current and the light power, while various angle modulations are enabled by the frequency chirp. Limited by the direct detection, DM lasers used to be exploited only as 1-D (intensity or angle) transmitters by suppressing or simply ignoring the other modulation. Nevertheless, through the digital coherent detection, simultaneous intensity and angle modulations (namely, 2-D complex DM, CDM) can be realized by a single laser diode...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437949/ultrafast-all-optical-solid-state-framing-camera-with-picosecond-temporal-resolution
#15
Guilong Gao, Kai He, Jinshou Tian, Chunmin Zhang, Jun Zhang, Tao Wang, Shaorong Chen, Hui Jia, Fenfang Yuan, Lingliang Liang, Xin Yan, Shaohui Li, Chao Wang, Fei Yin
A new ultrafast all-optical solid-state framing camera (UASFC) capable of single-shot ultrafast imaging is proposed and experimentally demonstrated. It is composed of an ultrafast semiconductor chip (USC), an optical time-series system (TSS), and a spatial mapping device (SMD) with an USC to transform signal beam information to the probe beam, a TSS to convert the time axis to wavelength-polarization, and a SMD to map wavelength-polarization image to different spatial positions. In our recent proof-of-principle experiment, better performance than ever of this technique is confirmed by giving six frames with ~3 ps temporal resolution and ~30 lp/mm spatial resolution...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437944/calibrating-high-intensity-absorption-imaging-of-ultracold-atoms
#16
Klaus Hueck, Niclas Luick, Lennart Sobirey, Jonas Siegl, Thomas Lompe, Henning Moritz, Logan W Clark, Cheng Chin
Absorption imaging of ultracold atoms is the foundation for quantitative extraction of information from experiments with ultracold atoms. Due to the limited exposure time available in these systems, the signal-to-noise ratio is largest for high intensity absorption imaging where the intensity of the imaging light is on the order of the saturation intensity. In this case, the absolute value of the intensity of the imaging light enters as an additional parameter making it more sensitive to systematic errors. Here, we present a novel and robust technique to determine the imaging beam intensity in units of the effective saturation intensity to better than 5%...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437942/optical-damage-resistant-ti-diffused-zr-er-codoped-lithium-niobate-strip-waveguide-for-high-power-980-nm-pumping
#17
Wen-Bao Sun, Xiao-Fei Yang, Zi-Bo Zhang, Wing-Han Wong, Dao-Yin Yu, Edwin Yue-Bun Pun, De-Long Zhang
Ti<sup>4+</sup>-diffused Zr<sup>4+</sup>/Er<sup>3+</sup>-codoped LiNbO<sub>3</sub> strip waveguide was fabricated on an X-cut LiNbO<sub>3</sub> substrate by thermal diffusion in sequence of Er<sup>3+</sup>, Zr<sup>4+</sup> and Ti<sup>4+</sup>. Secondary ion mass spectrometry study shows that the Ti<sup>4+</sup> ions follow a sum of two error functions in the width direction and a Gauss function in the depth direction of the waveguide...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437941/effect-of-scattering-on-coherent-anti-stokes-raman-scattering-cars-signals
#18
Janaka C Ranasinghesagara, Giuseppe De Vito, Vincenzo Piazza, Eric O Potma, Vasan Venugopalan
We develop a computational framework to examine the factors responsible for scattering-induced distortions of coherent anti-Stokes Raman scattering (CARS) signals in turbid samples. We apply the Huygens-Fresnel wave-based electric field superposition (HF-WEFS) method combined with the radiating dipole approximation to compute the effects of scattering-induced distortions of focal excitation fields on the far-field CARS signal. We analyze the effect of spherical scatterers, placed in the vicinity of the focal volume, on the CARS signal emitted by different objects (2μm diameter solid sphere, 2μm diameter myelin cylinder and 2μm diameter myelin tube)...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437940/rydberg-atom-based-radio-frequency-electrometry-using-frequency-modulation-spectroscopy-in-room-temperature-vapor-cells
#19
Santosh Kumar, Haoquan Fan, Harald Kübler, Akbar J Jahangiri, James P Shaffer
Rydberg atom-based electrometry enables traceable electric field measurements with high sensitivity over a large frequency range, from gigahertz to terahertz. Such measurements are particularly useful for the calibration of radio frequency and terahertz devices, as well as other applications like near field imaging of electric fields. We utilize frequency modulated spectroscopy with active control of residual amplitude modulation to improve the signal to noise ratio of the optical readout of Rydberg atom-based radio frequency electrometry...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437939/exploiting-high-order-phase-shift-keying-modulation-and-direct-detection-in-silicon-photonic-systems
#20
Jie You, Nicolae C Panoiu
A computational approach to evaluate the bit-error ratio (BER) in silicon photonic systems employing high-order phase-shift keying (PSK) modulation formats is presented. Specifically, the investigated systems contain a silicon based optical interconnect, namely a strip silicon photonic waveguide or a silicon photonic crystal waveguide, and direct-detection receivers suitable to detect PSK and amplitude-shaped PSK signals. The superposition of a PSK signal and complex additive white Gaussian noise passes through the optical interconnect and subsequently through two detection-branch receivers...
April 17, 2017: Optics Express
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