bluuebunny/crossref_metadata_2025 huggingface dataset:
Noise Effect and Stability of Deep-UV Gas-filled Fiber Lasers Pumped with Ultrafast Mid-IR Pulses
Authors: Adamu Abubakar I. , Habib Md. Selim , Smith Callum R. , Lopez J. Enrique Antonio , Jepsen Peter Uhd , Amezcua-Correa Rodrigo , Bang Ole , Markos Christos
Published: September 2020

Noise and spectral stability of dispersive waves generated in an argon-filled hollow-core fiber pumped with 2.4 μm ultrafast pulses is presented. Long-term stability and pulse-to-pulse relative intensity noise of the strongest dispersive wave at 275 nm is shown.
Thermal Effects in Molecular Gas-Filled Hollow-Core Fibers
Authors: Nrisimhamurty M. , Beetar John E. , Liu Yangyang , Chini Michael
Published: September 2020

Molecular gas-filled hollow-core fibers are attractive for pulse compression of Yb lasers. Here, we show that rotational heating prevents efficient spectral broadening at high average powers and find that buffer-gas cooling can mitigate this effect.
Spectral Broadening of Femtosecond UV Pulses in Air-filled Hollow-Core Photonic Crystal Fiber
Authors: Luan J. , Novoa D. , Russell P. St.J.
Published: September 2020

Air-filled kagomé-type photonic crystal fiber pumped by 40-fs pulses at 400 nm produces a spectrum with several nitrogen-related Raman bands that is broad enough to support transform-limited 7 fs pulses in the UV.
High-order Harmonic Generation in Femtosecond Laser Micromachined Devices for Ultrafast X-ray Spectroscopy
Authors: Ciriolo A. G. , Vâzquez R. Martinez , Tosa V. , Frezzotti A. , Cinquanta E. , Crippa G. , Devetta M. , Osellame R. , Stagira S. , Vozzi C.
Published: September 2020

We demonstrate efficient high-order harmonic generation in fused-silica chips fabricated by femtosecond laser micromachining. This work provides a route toward the miniaturization of HHG beamlines and the implementation of X-ray spectroscopy with attosecond temporal resolution.
Trains and Isolated Attosecond Pulses at 100 kHz
Authors: Furch Federico J. , Witting Tobias , Osolodkov Mikhail , Schell Felix , Menoni Carmen S. , Schulz Claus P. , Vrakking Marc J. J.
Published: September 2020

We report on the generation and characterization of trains and isolated attosecond pulses at a repetition rate of 100 kHz. This system will be utilized for attosecond pump-probe spectroscopy studies with electron-ion coincidence detection.
Experimental Demonstration of a 4D PDL-resilient Signaling for Long-haul Networks
Authors: Dumenil Arnaud , Awwad Elie , Measson Cyril , Le Gac Dylan
Published: September 2020

We experimentally demonstrate improvement of the worst-case information rate using the New Spatially Balanced (NSB) signaling recently proposed for PDL mitigation. NSB-coded and dual-polarization QPSK formats are compared over a multi-span link with inline PDL.
Switching Second-Harmonic Forward to Backward Emission via GaAs Nanoantennas
Authors: Xu L. , Saerens G. , Timofeeva M. , Smirnova D. A. , Volkovskaya I. , Lysevych M. , Camacho-Morales R. , Cai M. , Kamali K. Z. , Huang L. , Karouta F. , Tan H. H. , Jagadish C. , Miroshnichenko A. E. , Grange R. , Neshev D. N. , Rahmani M.
Published: September 2020

Switching forward-to-backward linear scattering of nanoantennas is a process of major importance. Here, we demonstrate the first nonlinear switching of forward to backward second harmonic generation, via engineering the nonlinear-tensors of the (110)-GaAs nanoantennas.
Millisecond Suppression of Counter-propagating Optical Signal using Ultrafast Laser Filaments
Authors: Skrodzki Patrick J. , Finney Lauren A. , Burger Milos , Nees John , Jovanovic Igor
Published: September 2020

We demonstrate millisecond-scale on-axis signal suppression using filament air plasmas formed by unaltered Gaussian beams with implications for background/continuum rejection for remote sensing applications.
Record-High Continuous-Wave Nonlinear Performance of Amorphous Silicon Waveguides
Authors: Girouard Peter , Frandsen Lars H. , Galili Michael , Oxenløwe Leif K.
Published: September 2020

We present an amorphous silicon material having a record-high continuous-wave L-band conversion efficiency of -14.7 dB. The material is stable over 12 hours of 23 dBm continuous-wave C-band pumping
Stable Harmonic Mode Locking in all PM-Fiber Mamyshev Oscillator
Authors: Piechal Bernard , Kardas Tomasz M. , Pielach Mateusz , Stepanenko Yuriy
Published: September 2020

We present the first o bservation of h armonic m ode l ocking i n Mamyshev oscillator. The Yb-doped all-PM oscillator emits 2 nJ pulses with repetition rate up to 229 MHz at 14th harmonic, limited by available pump power.
Ultrafast Multiphoton Absorption in Optical-Coating Materials at Near-Damage-Threshold Fluence
Authors: Gruzdev V. , Kafka K. R. P.
Published: September 2020

Multiphoton absorption substantially contributes to the initiation of laser damage of optical coatings by ultrashort laser pulses. Here we report a simulation approach to fix some assumptions of the traditional models violated at near-damage-threshold fluence.
Graphene Nanowalls Field Effect Structure Photodetector and Its Light Response Mechanism
Authors: Qian Fengsong , Dong Yibo , Hu Liangchen , Wang Qiuhua , Sun Jie , Xie Yiyang , Xu Chen
Published: September 2020

Graphene nanowalls were first used to prepare field effect structure photodetector, which has a responsivity ten times higher than that of monolayer graphene detector with the same structure.
Preparation of Few-layer Black Phosphorus with Enhanced Photoluminescence and Stability
Authors: Li Dongying , Yu Yueyang , Ning Cun-Zheng
Published: September 2020

We propose a method to prepare few-layer black phosphorus by oxygen plasma etching, followed by boron nitride encapsulation and thermal annealing. This method produces few-layer black phosphorus with strongly enhanced photoluminescence and greatly improved stability.
Liquid crystal-enhanced photophone cells
Authors: Dela Cruz Michael T. , Wang Ling , Chandrahalim Hengky
Published: September 2020

This paper demonstrates for the first time the intrinsic enhancing nature of liquid crystal to acoustically modulated light on a microscale platform. This study enables many advanced applications in optoacoustic sensing and signal processing.
Unravelling Ultrafast Excited State Absorption in Few Layer ReS2
Authors: Mandai Dipendranath , Marik Sourav , Sharma Sudarshan , Singh R. P. , Adarsh K. V.
Published: September 2020

Here we report excited-state absorption in few layer ReS2 using ultrafast pump-probe and nonlinear spectroscopy. The remarkable transition from reverse-saturable to two-photon absorption reveals its potential applications in optical limiting and switching.
Coherent Control with Vector Beams for Ultrafast Magnetic Pulses
Authors: Sederberg Shawn , Kong Fanqi , Hufnagel Felix , Karimi Ebrahim , Corkum Paul B.
Published: September 2020

We demonstrate coherent control in a semiconductor using vector laser beams and spatially map the resulting currents. Ring currents are excited using two configurations, and the potential for generating short, intense magnetic impulses is demonstrated.
A Deterministic Method for Obtaining Large-Bandwidth Frequency Combs in Microresonators with Thermal Effects
Authors: Qi Zhen , Jaramiüo-ViUegas Jose , D’Aguanno Giuseppe , Carruthers Thomas F. , Gat Omri , Weiner Andrew M. , Menyuk Curtis R.
Published: September 2020

We describe a deterministic method for obtaining large-bandwidth frequency combs in microresonators using cnoidal waves in the soliton crystal limit. We take thermal effects into account.
Photonic RF fractional Hilbert transformers and filters based on integrated soliton crystal microcombs
Authors: Xu Xingyuan , Tan Mengxi , Wu Jiayang , Nguyen Thach G. , Chu Sai T. , Little Brent E. , Morandotti Roberto , Mitchell Arnan , Moss David J.
Published: September 2020

We report photonic RF fractional Hilbert transformers and filters based on a 49GHz soliton crystal micro-comb source. By employing up to 80 wavelengths and controlling the channel weights, diverse transfer functions are achieved.
Coherent Architectures for Free-Space Optical Communications
Authors: Geisler David J.
Published: September 2020

Custom coherent architectures can provide many advantages for FSO communications systems through co-development of integrated photonics, ASIC- or FPGA-based DSP algorithms, and system design to mitigate atmospheric turbulence and reduce pointing requirements.
Mid-infrared photon-number-resolving detection based on efficient nonlinear frequency conversion
Authors: Kang Weiyan , Wu Jiamei , Liang Yan , Yan Ming , Huang Kun , Zeng Heping
Published: September 2020

We have implemented a coincidence-pumping frequency upconversion system with a nonlinear conversion efficiency up to 80%, which enabled to demonstrate high-performance midinfrared photon detection and photon-number-resolving capability at 3.1 pm.
Carrier-Envelope Offset-Free Pulse Train by Difference-Frequency Generation from a Si3N4-Waveguide Supercontinuum Output
Authors: Herda Robert , Kienle Florian , Seer Ali , Tresp Christoph , Niedermaier Evelyn , Anderson Miles , Kippenberg Tobias J. , Stroganov Anton , Navickaite Gabriele , Sacchetto Davide , Geiselmann Michael , Kaenders Wilhelm
Published: September 2020

We present a novel approach to generate a frequency comb based on Difference Frequency Generation (DFG). The frequency components required for the DFG process are generated in a Si3N4waveguide. A mode-locked 200 MHz oscillator is amplified in an Erbium-doped fiber, compressed to a duration of 42 fs and coupled into the waveguide. The power for generating the necessary spectral components in the waveguide is reduced by a factor of five compared to a setup based on highly nonlinear fiber.
Whole Brain Optical Access in Adult Vertebrates: Two- and Three-Photon Imaging in a Miniature Fish, Danionella priapus
Authors: Akbari Najva , Tatarsky Rose L. , Kolkman Kristine E. , Fetcho Joseph R. , Bass Andrew H. , Xu Chris
Published: September 2020

We use two- and three-photon microscopy to demonstrate in vivo, whole-brain neuroimaging in adult Danionella priapus, a miniature vertebrate species closely related to zebrafish (Danio rerio).
Compact, alignment-free, environmentally stable dispersion compensated femtosecond Yb-fiber oscillator
Authors: Ma Yuxuan , Salman Sarper , Li Chen , Mahnke Christoph , Fellinger Jakob , Mayer Aline S. , Heckl Oliver H. , Heyl Christoph M. , Hartl Ingmar
Published: September 2020

We demonstrate a fully integrated alignment free, femtosecond Yb:fiber laser operating in the stretched pulse regime. After compression, the laser provides a long-term stable output of 104 fs pulses at 76 MHz repetition rate.
1.6-1.7 um Wavelength Tunable, All-Polarization Maintaining, Dual-Comb Fiber Laser with Single Wall Carbon Nanotube for Dual Comb Spectroscopy
Authors: Nishizawa N. , Kanehara Y. , Yamanaka M. , Terabayashi R. , Omoda E. , Kataura H. , Sakakibara Y.
Published: September 2020

We developed 1.6-1.7 um wavelength tunable, polarization-maintaining dual comb fiber laser. Spectral width was controlled and wideband measurement was realized without bandpass filters. Absorption spectra of CH4 gas was observed in this wide range.
Femtosecond Nd:fiber laser at 920nm mode-locked by biased NALM
Authors: Wang Siying , Li Yijun , Chen Yanchuan , Gao Yuqian , Zhang Zhigang , Wang Aimin
Published: September 2020

We demonstrate a mode-locked NALM polarization-maintaining Nd:fiber laser at 920 nm with a repetition rate of 43.6 MHz. The average output power is 8 mW and the pulse width is 109 fs.
Multifunctional space–time phase modulated graphene metasurface
Authors: Kashef Mohammad Mahdi , Ghattan Kashani Zahra
Published: September 2020

Metasurfaces provide special features for manipulating electromagnetic wavefronts that are not possible with conventional optical devices. A common approach in designing metasurfaces has been the use of spatially varying metallic and/or dielectric nanoantennas separated with a subwavelength distance to obtain the required local phase change yielding the desired optical performance. In this paper, we propose a space–time phase modulation technique based on a graphene metasurface with the possibility of actively manipulating the electromagnetic wavefront. In this technique, we utilize graphene microribbon arrays that exhibit resonant behavior at terahertz (THz) frequencies. By applying an alternating voltage with a particular modulation frequency and phase, the time-dependent changes in the complex refractive indices of the graphene ribbons can be induced. This phenomenon results in the active control of the reflection amplitude and phase and the generation of the harmonic frequencies in the output reflection spectra. Theoretically, by using the Floquet analysis, it is shown that the reflected wave has harmonic frequencies, and the phase of the reflection wave at each harmonic component changes through changing the modulation phase of each graphene ribbon. The performance of the wavefront manipulation technique is evaluated using the finite difference time domain method and the circuit model. The results of the proposed circuit model are in good agreement with those of the full-wave simulation. Additionally, the applications of the proposed space–time phase modulated graphene metasurface for realizing an anomalous reflector and a lens with a tunable focal length are explained in detail.
Ultracompact gas sensor with metal-organic-framework-based differential fiber-optic Fabry-Perot nanocavities
Authors: Kim Hyun-Tae , Hwang Wonseok , Liu Yun , Yu Miao
Published: September 2020

Refractive-index (RI)-based sensing is a major optical sensing modality that can be implemented in various spectral ranges. While it has been widely used for sensing of biochemical liquids, RI-based gas sensing, particularly small-molecule gases, is challenging due to the extremely small RI change induced by gas concentration variations. We propose a RI-based ultracompact fiber-optic differential gas sensor that employs metal-organic-framework (MOF)-based dual Fabry-Perot (FP) nanocavities. A MOF is used as the FP cavity material to enhance the sensitivity as well as the selectivity to particular gas molecules. The differential sensing scheme leverages the opposite change in the cavity-length-dependent reflection of the two FP cavities, which further enhances the sensitivity compared with single FP cavity based sensing. For proof-of-concept, a fiber-optic CO2 sensor with ZIF-8-based dual FP nanocavities was fabricated. The effective footprint of the sensor was as small as 157 µm2 and the sensor showed an enhanced sensitivity of 48.5 mV/CO2Vol%, a dynamic range of 0-100 CO2Vol%, and a resolution of 0.019 CO2Vol% with 1 Hz low-pass filtering. Although the current sensor was only demonstrated for CO2 sensing, the proposed sensor concept can be used for sensing of a variety of gases when different kinds of MOFs are utilized.
All-optical negative differential transporter of Bose-Einstein condensates in cavity
Authors: Xia Xiuwen , Zhang Xinqin , Xu Jingping , Li Haozhen , Li Na , Yang Yaping
Published: September 2020

We present a new and interesting physical phenomenon of optical negative differential transmission (ONDT, whose output intensity decreases with the increasing of input field intensity for an arbitrary optical system) in present BEC-cavity coupling system which pumped by a strong light and probed by a weak light. Theoretical results show that the transmission of the probe can be suppressed or promoted greatly by the pump due to optical nonlinearity and the Stokes/anti-Stokes scattering. To our most interest, two kinds of ONDT respectively induced by the nonlinear incoherent light-controlling and the nonlinear coherent interference have been uncovered, which have promising prospect in producing hyper-stable light source since it provides an unusual negative feedback.
Numerical analyses of optical loss and modulation bandwidth of an InP organic hybrid optical modulator
Authors: Sekine Naoki , Toprasertpong Kasidit , Takagi Shinichi , Takenaka Mitsuru
Published: September 2020

We numerically analyzed the modulation characteristics of an InP organic hybrid (IOH) optical modulator consisting of an InP slot waveguide and an electro-optic (EO) polymer. Since InP has a higher electron mobility and a lower electron-induced free-carrier absorption than Si, the series resistance of an InP slot waveguide can be significantly reduced with relatively smaller optical loss than an Si slot waveguide. As a result, the trade-off between optical loss and modulation bandwidth can be remarkably improved compared with a Si organic hybrid (SOH) optical modulator. When the modulation bandwidth was designed to be 100 GHz, the optical loss of the IOH modulator was 13-fold smaller than that of the SOH one. The simulation of the eye diagram revealed that the improved optical modulation amplitude enabled the clear eye opening with a 100 Gbps non return-to-zero signal using the IOH modulator. The IOH integration is promising for a high-speed modulator with low energy consumption beyond 100 Gbps.
Femtosecond dual-comb Yb:CaF2 laser from a single free-running polarization-multiplexed cavity for optical sampling applications
Authors: Willenberg Benjamin , Pupeikis Justinas , Krüger Léonard M. , Koch Florian , Phillips Christopher R. , Keller Ursula
Published: September 2020

Dual optical frequency combs are an appealing solution to many optical measurement techniques due to their high spectral and temporal resolution, high scanning speed, and lack of moving parts. However, industrial and field-deployable applications of such systems are limited due to a high-cost factor and intricacy in the experimental setups, which typically require a pair of locked femtosecond lasers. Here, we demonstrate a single oscillator which produces two mode-locked output beams with a stable repetition rate difference. We achieve this via inserting two 45°-cut birefringent crystals into the laser cavity, which introduces a repetition rate difference between the two polarization states of the cavity. To mode-lock both combs simultaneously, we use a semiconductor saturable absorber mirror (SESAM). We achieve two simultaneously operating combs at 1050 nm with 175-fs duration, 3.2-nJ pulses and an average power of 440 mW in each beam. The average repetition rate is 137 MHz, and we set the repetition rate difference to 1 kHz. This laser system, which is the first SESAM mode-locked femtosecond solid-state dual-comb source based on birefringent multiplexing, paves the way for portable and high-power femtosecond dual-combs with flexible repetition rate. To demonstrate the utility of the laser for applications, we perform asynchronous optical sampling (ASOPS) on semiconductor thin-film structures with the free-running laser system, revealing temporal dynamics from femtosecond to nanosecond time scales.
Phase sensitive low-coherence interferometry using microwave photonics
Authors: Clement Juan , Maestre Haroldo , Torregrosa Germán , Fernández-Pousa Carlos R.
Published: September 2020

We report on a low-coherence interferometer based on Microwave Photonics (MWP) which allows, for the first time to the best of our knowledge, stable determination of the interferogram’s phase. The interferometer is built on suppressed carrier, double-sideband modulation, dispersive propagation in a chirped fiber Bragg grating, demodulation by electro-optical frequency down-conversion, and suitable signal processing techniques to account for modulation impairments. Taking as a reference a direct normalization of the link’s microwave response, the system retrieves high-resolution interferograms, both in amplitude and phase and free from distortion induced by higher-order dispersion, in an optical path difference of 16.3 mm, surpassing previously reported values based on MWP implementations. We present representative applications targeted to the characterization of C-band sources and components, such as direct analysis of interferograms with 5.5 fs temporal resolution, Fourier-transform spectroscopy with 14 GHz spectral resolution, and optical low-coherence reflectrometry of the impulse response’s amplitude of fiber Bragg gratings with 0.55 μm spatial resolution.
Mode transmission analysis method for photonic lantern based on FEM and local coupled mode theory
Authors: Chen Siyu , Liu Yan-ge , Wang Zhi , Guo Huiyi , Zhang Hongwei , Mao Baiwei
Published: September 2020

In this paper, a novel full vector numerical simulation method based on the finite element method (FEM) and local coupled mode theory (LCMT) for analyzing the mode transmission characteristics of photonic lantern (PL) with arbitrary input mode field is proposed. Compared with the traditional numerical simulation methods for PL, our method can greatly reduce the computational complexity and ensure high precision. Taking a three-core PL as an example, we verify the validity of our method. The advantages and properties of our method are also discussed in detail and found instructive for optimization design of PL. Through specifically optimizing the geometric parameters of the PL according to the properties, mode selectivity of LP01 and LP11 can be respectively improved up to 44.5 dB and 54.7 dB with more than 95% coupling efficiency.
Asymmetric transmission of linearly polarized waves based on Mie resonance in all-dielectric terahertz metamaterials
Authors: Rao Yunfei , Pan Ling , Ouyang Chunmei , Xu Quan , Liu Liyuan , Li Yanfeng , Gu Jianqiang , Tian Zhen , Han Jiaguang , Zhang Weili
Published: September 2020

Interest in asymmetric transmission (AT) at terahertz frequencies has increased dramatically in recent years. We present an all-silicon metamaterial to achieve the AT effect for linearly polarized electromagnetic waves in the terahertz regime. The metamaterial is constructed by rectangular silicon pillars and a thick silicon substrate. The magnetic Mie resonance excited by the incident polarized terahertz wave contributes to the AT effect, which is verified by the field distributions. In addition, the rotation angle and dimensions of the silicon pillars are shown to have a great influence on the AT efficiency. The proposed metamaterial with straightforward design has promising applications in polarization control scenarios.
Designing high-performance nighttime thermoradiative systems for harvesting energy from outer space
Authors: Zhang Xin , Du Jianying , Chen Jincan , Ang Lay Kee , Ang Yee Sin
Published: September 2020

Energy harvesting using thermoradiative systems has been extensively explored in recent years as a novel strategy for further reducing our energy footprint. However, the nighttime application, thermodynamic limit, and optimal design of such a system remain largely unaddressed so far. Here we propose an improved nighttime thermoradiative system (NTS) for electrical power generation by optically coupling Earth’s surface with outer space. Our theoretical model predicts that the NTS operating with Earth (deep space) at 300 K (3 K) yields a maximum power density of

12.3

W
m

−
2

with an efficiency limit of 18.5%, which is potentially more advantageous than previous nighttime energy harvesting systems, such as a nighttime thermoelectric generator. We find that optimizing the thickness of the active layer, enhancing thermal infrared emission, and employing a silver backreflector for photon recycling are crucially important in improving system performance. This Letter provides new insights for the optimal designs of NTSs and paves the way toward practical nighttime power generation.
Megahertz-rate OH planar laser-induced fluorescence imaging in a rotating detonation combustor
Authors: Hsu Paul S. , Slipchenko Mikhail N. , Jiang Naibo , Fugger Christopher A. , Webb Austin M. , Athmanathan Venkat , Meyer Terrence R. , Roy Sukesh
Published: September 2020

Megahertz-rate hydroxyl radical planar laser-induced fluorescence (OH-PLIF) was demonstrated in a hydrogen/air rotating detonation combustor for the first time, to the best of our knowledge. A custom injection-seeded optical parametric oscillator (OPO) pumped by the 355 nm output of a high-energy burst-mode laser produced narrowband pulses near 284 nm for OH excitation. The system generated sequences of more than 150 ultraviolet pulses with 400 µJ/pulse at 1 MHz and 150 µJ/pulse at 2 MHz. The order of magnitude improvement in the repetition rate over prior OH-PLIF measurements and in the number of pulses over previous megahertz burst-mode OPOs enables spatiotemporal analysis of complex detonation combustion dynamics.
Extrinsic optical activity in all-dielectric terahertz metamaterial
Authors: Yang Shijun , Li Yanfeng , Chen Xieyu , Yang Quanlong , Han Jiaguang , Zhang Weili
Published: September 2020

Chiral metamaterials have attracted wide interest because strong optical activity at designed frequencies could be achieved beyond that in natural materials. Here we propose an all-dielectric metamaterial with strong extrinsic circular dichroism and circular birefringence by periodically arranging symmetry-broken dielectric Mie resonators at terahertz frequencies. The strong interaction between the electric and magnetic resonances from circularly polarized incident waves dominates the performance of the all-dielectric metamaterial, which exhibits a 60% circular dichroism in transmission and a polarization rotation angle of 60° at maximum, respectively. Additionally, the spectral range of the circular dichroism with preserved amplitude can be adjusted continuously in the frequency range from 0.67–0.79 THz by tuning the tilt angle of the incident wave. Our findings will be of great potential in polarization control applications such as asymmetric transmission, optical isolation, and on-chip chiral manipulation.
Unitary matrix approach for a precise voltage dependent characterization of reflective liquid crystal devices by average Stokes polarimetry
Authors: Márquez Andrés , Martínez-Guardiola Francisco J. , Francés Jorge , Calzado Eva M. , Puerto Daniel , Gallego Sergi , Pascual Inmaculada , Beléndez Augusto
Published: September 2020

Precise characterization of parallel-aligned liquid crystal on silicon microdisplays has an important impact in many advanced photonics applications. We show liquid crystal on silicon (LCoS) modeled as a non-absorbent reciprocal device. Combined with time-average Stokes polarimetry, LCoS enables us to demonstrate robust measurements across the whole applied voltage range for the retardance and its flicker, and also as a novelty for the director orientation. We obtain that the director orientation changes across the voltage range, especially at larger applied voltages. This is a small effect, but it may provide a deeper insight into the internal dynamics in the liquid crystal layer, and in sensitive phase-only applications will produce a coupling between amplitude and phase.
Efficient, sub-4-cycle, 1-µm-pumped optical parametric amplifier at 10  µm based on BaGa4S7
Authors: Heiner Zsuzsanna , Petrov Valentin , Mero Mark
Published: September 2020

We report on a microjoule-scale mid-infrared optical parametric amplifier (OPA) based on the recently developed wide-bandgap orthorhombic crystal,

B
a
G

a

4

S

7

(BGS) and directly compare its performance to that of

L
i
G
a

S

2

(LGS) in the same OPA setup. The source is based on a single OPA stage amplifying supercontinuum seed pulses with a quantum efficiency of 29% at an idler wavelength of 10 µm, featuring nominally carrier-envelope phase-stable pulses. As a result of pumping the OPA directly at 1 µm, the overall conversion efficiency far exceeds that of traditional schemes based on OPAs followed by difference frequency generation. Chirp compensation using bulk germanium resulted in 126 fs pulses covering the 7.6–11.5 µm spectral range. BGS holds great promise for power scaling due to its availability in larger single-crystal sizes than LGS.
Electro-optically spectrum switchable, multiwavelength optical parametric oscillators based on aperiodically poled lithium niobate
Authors: Wang Tai-Jie , Deng Lin-Ming , Chung Hung-Pin , Chang Wei-Kun , Pham Tien-Dat , Tseng Quan-Hsiang , Geiss Reinhard , Pertsch Thomas , Chen Yen-Hung
Published: September 2020

We report the first fast switchable multiwavelength optical parametric oscillator based on aperiodic optical superlattice technology. The constructed aperiodically poled lithium niobate (APPLN) integrates the functionalities of two quasi-phase-matching devices on a chip to work simultaneously as an electro-optic (EO) switchable notch-like filter and a multiline optical parametric downconverter. When such an APPLN is built in a 1064-nm-pumped optical resonator system, we achieve the oscillation of dual signals at 1540 and 1550 nm, for a single signal at 1540 nm, and a single signal at 1550 nm in the system when the 3-cm-long APPLN is driven by 0 V, 354 V, and 805 V, respectively. The switching among the three signal spectra is operationally simple and electro-optically fast. The electro-optically switched signals also feature enhanced power spectral density due to the unique EO gain-spectrum filtering mechanism employed in this work.
Ultra-fast Stokes parameter correlations of true unpolarized thermal light: type-I unpolarized light
Authors: Kroh Florian , Rosskopf Markus , Elsässer Wolfgang
Published: September 2020

We measure Stokes parameter correlations in analogy to the intensity correlation measurements in the original Hanbury-Brown & Twiss configuration by realizing an experimental setup by combining a Schaefer–Collett or Berry–Gabrielse–Livingston polarimeter with a Hanbury-Brown & Twiss intensity interferometer. We investigate true unpolarized light emitted from a broadband thermal light source, which we realize by an erbium-doped fiber amplifier, thus being an ideal source of true unpolarized light. We find that all Stokes parameter correlations⟨SnSn⟩,n∈{1,2,3}are equal to0.5⟨I⟩2. The proven invariance of the Stokes parameter correlations against retardation by wave-plates clearly shows for the first time, to the best of our knowledge, that our true unpolarized thermal light represents type I unpolarized light in accordance with a theoretical prediction for a classification of unpolarized light postulated more than 20 years ago.
Long interior carrier lifetime in selective-area InAs nanowires on silicon
Authors: Zhang Kailing , Li Xinxin , Walhof Alexander C. , Liu Yuzi , Toor Fatima , Prineas John P.
Published: September 2020

Catalyst-free, position-controlled indium arsenide (InAs) nanowires (NWs) of variable diameters were grown on Si (111) by selective-area epitaxy (SAE). Ultrafast pump-probe spectroscopy was conducted, from which carrier recombination mechanisms on the NW surface and interior were resolved and characterized. NWs grown using SAE demonstrated high optical quality, showing minority carrier lifetimes more than two-fold longer than that of the randomly-positioned (RP) NWs. The extracted SAE-InAs NW interior recombination lifetime was found to be as long as 7.2 ns, 13X longer than previous measurements on RP-NWs; and the surface recombination velocity 4154 cm · s- 1. Transmission electron microscopy revealed a high density of stacking defects within the NWs, suggesting that interior recombination lifetime can be further increased by improving NW interior crystalline quality.
Broadband infrared and THz transmitting silicon core optical fiber
Authors: Sørgård Trygve , Song Seunghan , Vullum Per Erik , Kores Cristine , Mølster Kjell Martin , Laurell Fredrik , Hawkins Thomas , Ballato John , Österberg Ulf L. , Gibson Ursula J.
Published: September 2020

Silicon waveguide structures are a viable alternative for the transmission of signals over a wide range of frequencies, and new fabrication methods are key to increased applications. In this work, THz transparency of silicon-core, silica clad fibers, refined using a traveling solvent method, is demonstrated. The ≈ 200 µm core of these fibers is shown to have good transmission from 4.8–9 µm and 1–7 THz. Fibers were drawn on a conventional optical fiber tower using the scalable molten core technique and CO2 laser annealed, resulting in large-grain crystalline cores with broadband transmission. The spectral properties are comparable to those of rectangular guides of similar cross-sectional area cut from high resistivity float zone silicon wafers.
Phosphorylated Alpha-Synuclein Within Cutaneous Autonomic Nerves of Patients With Parkinson’s Disease: The Implications of Sample Thickness on Results
Authors: Wang Ningshan , Garcia Jennifer , Freeman Roy , Gibbons Christopher H.
Published: September 2020

The detection of cutaneous phosphorylated alpha-synuclein (P-syn) in patients with Parkinson’s disease (PD) has ranged from 30% to 100% across different studies. We hypothesize that part of the variability in P-syn detection is due to methodological differences using sections of different tissue thickness. Three skin biopsies were obtained from 29 individuals with PD and 21 controls. Tissues were cut into 10-, 20-, and 50-µm-thick sections and double-stained with protein gene product (PGP) 9.5 and P-syn. We quantified the deposition of P-syn with and without PGP 9.5 in sweat glands, pilomotor muscle, and blood vessels using confocal digital images of autonomic structures. Overall, the P-syn-positive rates with PGP 9.5 colocalization in subjects with PD were 100% using 50 µm sections, 90% using 20 µm sections, and 73% using 10 µm sections with 100% specificity. (No P-syn was detected within control subjects.) Without PGP 9.5, colocalization of the P-syn-positive rates was 100% for all samples, but specificity dropped below 70%. In this study, double-immunostained 50 µm skin biopsy tissue sections are superior to 20 and 10 µm tissue sections at detecting P-syn in subjects with PD. The increased sensitivity is likely secondary to a combination of greater volume of tissue analyzed and improved visualization of nerve fiber architecture.
Assessing local trends in indicators of ecosystem services with a time series of forest resource maps
Authors: Katila Matti , Rajala Tuomas , Kangas Annika
Published: September 2020

Since the 1990âs, forest resource maps and small area estimates have been produced by combining national forest inventory (NFI) field plot data, optical satellite images and numerical map data using a non-parametric -nearest neighbour method. In Finland, thematic maps of forest variables have been produced by the means of multi-source NFI (MS-NFI) for eight to ten times depending on the geographical area, but the resulting time series have not been systematically utilized. The objective of this study was to explore the possibilities of the time series for monitoring the key ecosystem condition indicators for forests. To this end, a contextual Mann-Kendall (CMK) test was applied to detect trends in time-series of two decades of thematic maps. The usefulness of the observed trends may depend both on the scale of the phenomena themselves and the uncertainties involved in the maps. Thus, several spatial scales were tested: the MS-NFI maps at 16 Ã 16 m pixel size and units of 240 Ã 240 m, 1200 Ã 1200 m and 12â000 Ã 12â000 m aggregated from the MS-NFI map data. The CMK test detected areas of significant increasing trends of mean volume on both study sites and at various unit sizes except for the original thematic map pixel size. For other variables such as the mean volume of tree species groups, the proportion of broadleaved tree species and the stand age, significant trends were mostly found only for the largest unit size, 12â000 Ã 12â000 m. The multiple testing corrections decreased the amount of significant -values from the CMK test strongly. The study showed that significant trends can be detected enabling indicators of ecosystem services to be monitored from a time-series of satellite image-based thematic forest maps.k22222p
RNA Vaccine: The Future of Medical Science and Vaccinology
Authors: Patel Mahnoor
Published: September 2020

An attractive approach to vaccination is presented by nucleic acid vaccines. These vaccines based on DNA or RNA encoded with specific antigen and generally regarded as safe, effective which can mimic live infection with low rise of reversion to virulence. RNA vaccines generally elicit humoral as well as cellular immune response. Personalized medicine is the new paradigm of medical science for targeting specific characteristics of each individual by using their genetic profile to identify particular nature of the medical condition and design a unique treatment for each patient. Cancer immunotherapy stimulates a host antitumor immune response which can able to lead tumor shrinkage for the improvement of clinical outcomes in cancer patients. Eradication of the large tumor by active immunotherapy is the biggest challenge, to overcome this challenge combination therapy of mRNA vaccine with radiation can be effective. mRNA as a vaccine have many advantages including large scale production under GMP conditions is comparatively easy and robust, thats why inexpensive in contrast to the other biopharmaceuticals. The tumor antigens are recognizing by the immune system and this is the basis for cancer immunotherapy development.
Primary Colonic Lymphoma With Paraneoplastic Hypercalcemia
Authors: Augustine Thomas , Perisetti Abhilash , Khan Salman Ali , Lobo Rodolfo Henrich , Tharian Benjamin
Published: September 2020

Primary colonic lymphoma is a rare tumor accounting for 0.1%–0.5% of all colorectal malignancies. We describe a 63-year-old man whose initial presentation was altered mental status due to hypercalcemia. Physical examination revealed a hard, right-sided abdominal mass. Abdominal computed tomography showed a mass in the ascending colon, which on further evaluation with colonoscopy and biopsy was diagnosed as diffuse large B-cell lymphoma. A diagnosis of primary colonic lymphoma was made based on the Dawson criteria, after ruling out any extracolonic involvement. Workup for hypercalcemia showed elevated calcitriol levels, which is a paraneoplastic manifestation of the lymphoma.
SENSITIVITY ANALYSIS OF INPUT PARAMETERS FOR LOAD CARRYING CAPACITY OF MASONRY ARCH BRIDGES
Authors: Vokál Marek , Drahorád Michal
Published: September 2020

The article deals with an analysis of railway masonry arch bridges. Typical attributes of these bridges are pointing loss and backfill. Therefore, the material - masonry - behaviour can be described only by a non-linear stress-strain diagram, mainly because of low or no tensile strength. The load carrying capacity, which is one of the main parameters when assessing the bridge, is a non-linear problem with many inputs, such as properties of backfill and masonry, backfill depth and geometry of the arch. Some of these parameters can be obtained by a diagnostic survey or from archival documentation. Some of these parameters impact the calculation greatly and some negligibly. The identification of key parameters, which must be stated by the diagnostic survey, is the goal of this article.
Custo de produção e análise de eficiência econômica de feijões especiais em Goiás
Authors: Fernandes Lima Waleska Maria , Elenor Wander Alcido , Da Silva Medina Gabriel
Published: September 2020

O presente estudo visa verificar a viabilidade agroeconômica da produção de grãos especiais de feijão na terceira safra, no estado de Goiás. Para tanto, foram estimados os custos de produção dos cultivares de grãos especiais BRS Embaixador, BRS Executivo e BRS, além do cultivar de grão carioca BRS Estilo. Foram utilizados coeficientes de eficiência econômica (renda líquida, ponto de nivelamento, produtividade total dos fatores e taxa de retorno, entre outros). Identificamos que a viabilidade agroeconômica é apresentada apenas no cultivar BRS Embaixador que ao preço de venda considerado, gerou renda líquida de R$ 650,19 e taxa de retorno de 11%.
Concessão de Crédito Rural: evidências empíricas do impacto na produção de soja no Centro-Oeste brasileiro
Authors: Teodoro Santos Roberta , Silva Brandão Lorena , Almeida Luz Maria Luiza , Madeira Nogueira Jorge , Monsueto Sandro Eduardo
Published: September 2020

Este estudo examina o impacto do crédito rural sobre a produção de soja no Centro-Oeste brasileiro. As análises foram desenvolvidas a partir de informações da produção agrícola municipal e do volume de crédito rural destinado às atividades de custeio e de investimento, nos anos de 2009 e 2017, para os 467 municípios da região Centro-Oeste. O quociente locacional foi utilizado para verificar o nível de concentração relativa do mercado de crédito rural e da produção de soja. Os efeitos regionais e do crédito rural sobre a produção de soja foram estimados por meio de regressão econométrica. Os resultados apontam que a concessão de crédito rural possui efeitos positivos e significativos na produção de soja, sendo o resultado maior para o custeio em comparação com o investimento. Neste cenário, a política de crédito rural permanece como um instrumento essencial de estímulo governamental ao setor.
Baran
Authors: Mahdavi Mohammad , Abedjan Ziawasch
Published: September 2020

Traditional error correction solutions leverage handmaid rules or master data to find the correct values. Both are often amiss in real-world scenarios. Therefore, it is desirable to additionally learn corrections from a limited number of example repairs. To effectively generalize example repairs, it is necessary to capture the entire context of each erroneous value. A context comprises the value itself, the co-occurring values inside the same tuple, and all values that define the attribute type. Typically, an error corrector based on any of these context information undergoes an individual process of operations that is not always easy to integrate with other types of error correctors. In this paper, we present a new error correction system, Baran, which provides a unifying abstraction for integrating multiple error corrector models that can be pretrained and updated in the same way. Because of the holistic nature of our approach, we generate more correction candidates than state of the art and, because of the underlying context-aware data representation, we achieve high precision. We show that, by pretraining our models based on Wikipedia revisions, our system can further improve its overall precision and recall. In our experiments, Baran significantly outperforms state-of-the-art error correction systems in terms of effectiveness and human involvement requiring only 20 labeled tuples.
2R
Authors: Kang Minji , Choi Soyee , Oh Gihwan , Lee Sang-Won
Published: September 2020

Given skewed writes common in databases, the conventional
1R-Greedy
FTL incurs huge write amplification, most of which is contributed by cold pages amounting to 80% of data. Since
1R-Greedy
manages all flash blocks in
one region
at no type distinction, cold pages will be mixed with non-cold ones in the same blocks, spread across blocks over time, and thus repeatedly relocated upon garbage collections.

In this paper, we propose
"two region"
FTL (2R in short); with two flash regions of normal and cold, it focuses on isolating cold pages into cold region and thus preventing their repetitive relocations. 2R has two versions. The optimized version,
2R-FIFO
, can further prevent the problem of false cold pages in the basic version,
2R-Greedy
, by taking FIFO instead of Greedy as its victim selection policy. 2R is unique in that all its design decisions, including page placement and migration between regions, cold page identification, victim block selection, and space allocation among regions, capitalize on workload characteristics such as write skews, temporal locality, and frozen pages. Thanks to the principled approach, 2R is, unlike the existing hot/cold separation FTLs, a statistics-free and practical solution which can efficiently and effectively separate cold pages using only two regions.

Experimental results using a real OpenSSD as well as trace-driven simulations confirm that
2R-FIFO
can, compared to
1R-Greedy
, halve the write amplification in two OLTP benchmarks, TPC-C and LinkBench, thereby doubling IO performance and transaction throughput. In particular, as flash storage becomes nearly full,
2R-FIFO
starts outperforming
1R-Greedy
by 4x or more.
Topic-based community search over spatial-social networks
Authors: Al-Baghdadi Ahmed , Lian Xiang
Published: September 2020

Recently, the community search problem has attracted significant attention, due to its wide spectrum of real-world applications such as event organization, friend recommendation, advertisement in e-commence, and so on. Given a query vertex, the community search problem finds dense subgraph that contains the query vertex. In social networks, users have multiple check-in locations, influence score, and profile information (keywords). Most previous studies that solve the CS problem over social networks usually neglect such information in a community. In this paper, we propose a novel problem, named
community search over spatial-social networks
(TCS-SSN), which retrieves community with high social influence, small traveling time, and covering certain keywords. In order to tackle the TCS-SSN problem over the spatial-social networks, we design effective pruning techniques to reduce the problem search space. We also propose an effective indexing mechanism, namely
social-spatial
index, to facilitate the community query, and develop an efficient query answering algorithm via index traversal. We verify the efficiency and effectiveness of our pruning techniques, indexing mechanism, and query processing algorithm through extensive experiments on real-world and synthetic data sets under various parameter settings.
Efficient oblivious database joins
Authors: Krastnikov Simeon , Kerschbaum Florian , Stebila Douglas
Published: September 2020

A major algorithmic challenge in designing applications intended for secure remote execution is ensuring that they are oblivious to their inputs, in the sense that their memory access patterns do not leak sensitive information to the server. This problem is particularly relevant to cloud databases that wish to allow queries over the client's encrypted data. One of the major obstacles to such a goal is the join operator, which is non-trivial to implement obliviously without resorting to generic but inefficient solutions like Oblivious RAM (ORAM).

We present an oblivious algorithm for equi-joins which (up to a logarithmic factor) matches the optimal
O
(
n
log
n
) complexity of the standard non-secure sort-merge join (on inputs producing
O
(
n
) outputs). We do not use use expensive primitives like ORAM or rely on unrealistic hardware or security assumptions. Our approach, which is based on sorting networks and novel provably-oblivious constructions, is conceptually simple, easily verifiable, and very efficient in practice. Its data-independent algorithmic structure makes it secure in various different settings for remote computation, even in those that are known to be vulnerable to certain side-channel attacks (such as Intel SGX) or with strict requirements for low circuit complexity (like secure multiparty computation). We confirm that our approach is easily realizable by means of a compact implementation which matches our expectations for performance and is shown, both formally and empirically, to possess the desired security characteristics.