bluuebunny/crossref_metadata_2025 huggingface dataset:
Giant Enhancement of Photovoltage from InGaAs-Channel Dual-Grating-Gate HEMT THz Detector due to Nonlinear Rectification Effect at InGaAs/InAlAs Heterobarrier
Authors: Satou Akira , Hosotani Tomotaka , Negoro Takumi , Takida Yuma , Ito Hiromasa , Minamide Hiroaki , Otsuji Taiichi
Published: August 2021

We experimentally demonstrate the photovoltage from an InGaAs-channel dual-grating-gate HEMT THz detector in the gate-readout configuration is significantly enhanced by the positive gate bias application due to the nonlinear rectification effect at the InGaAs/InAlAs heterobarrier.
Broadband Terahertz Time-Domain Imaging Using a Terahertz Focal-Plane Array
Authors: Li Xurong , Jarrahi Mona
Published: August 2021

We present a terahertz time-domain imaging modality based on a terahertz focal-plane array. The imaging system has more than a 60-dB signal-to-noise ratio and can resolve terahertz images up to 2.5 THz.
Engineering quantum states by fiber-based SU(1,1) nonlinear interferometers
Authors: Li Xiaoying
Published: August 2021

Modes of photons play essential roles in interference. Using the fiber-based nonlinear interferometry that separates the nonlinear gain control from dispersion engineering, we show a new approach of modifying the mode structure of quantum state.
Generation of 70-nJ and 40-fs Pulses by a Ring Mamyshev Oscillator with a Single Gain Segment
Authors: Haig Henry , Sidorenko Pavel , Thorne Robert , Wise Frank W.
Published: August 2021

We present a ring-type Mamyshev oscillator with only one amplification stage. The design allows self-starting via modulation of the pump power, high pulse performance, and is suitable for all-fiber integration.
Tuning Light-Hole Optical Transition in Highly Tensile Strained Germanium Quantum Wells
Authors: Attiaoui Anis , Assali Simone , Del-Vecchio Patrick , Nicolas Jérôme , Moutanabbir Oussama
Published: August 2021

A new low-dimensional system consisting of a highly tensile strained Germanium quantum well (QW) was epitaxially grown on Si wafers using GeSn as barriers. The thickness of the well was modulated from 12.5nm, down to 1.5nm, whereas the tensile strain was increased from 1.1% to 1.67%. Infrared spectroscopic ellipsometry was used to investigate the optical activity of the QWs.
Intra-Burst Temporal Pulse Contrast of a High-Power Post-Compressed Picosecond Yb:YAG Laser
Authors: Viotti Anne-Lise , Alisauskas Skirmantas , Escoto Esmerando , Tünnermann Henrik , Dudde Katharina , Seidel Marcus , Manschwetus Bastian , Hartl Ingmar , Heyl Christoph M.
Published: August 2021

We report on pulse contrast characterization of the output of a gas-filled multi-pass cell employed for 20-fold compression of a high-power Yb:YAG laser. We demonstrate an energy content of 80% in the compressed fs pulse.
Kerr-lens mode-locked Tm:(Lu,Sc)2O3 ceramic laser generating sub-60-fs pulses at 2.08 µm
Authors: Zhao Yongguang , Yang Hanlin , Jing Wei , Huang Hui , Liu Jiachen , Pan Zhongben , Wang Zhengping , Xu Xinguang , Mateos Xavier , Loiko Pavel , Wang Yicheng , Wang Li , Chen Weidong , Griebner Uwe , Petrov Valentin
Published: August 2021

We report on a purely Kerr-lens mode-locked Tm:(Lu,Sc)2O3 ceramic laser emitting at 2083 nm. Nearly Fourier-transform-limited 58-fs pulses are generated with an average output power of 220 mW at a repetition rate of 84.8 MHz.
Highly efficient mid-infrared difference-frequency generation based on passively synchronous seeding
Authors: Wang Yinqi , Fang Jianan , Yan Ming , Huang Kun , Zeng Heping
Published: August 2021

A watt-level ultrafast mid-infrared source was implemented based on difference-frequency generation with passively synchronous seeding, which favored a much lower pumping threshold and a maximum power conversion efficiency of 77%.
Multi-Beam Integration for On-chip Quantum Devices
Authors: Ropp Chad , Yulaev Alexander , Zhu Wenqi , Westly Daron A. , Simelgor Gregory , Agrawal Amit , Papp Scott , Aksyuk Vladimir
Published: August 2021

We photonically generate 12 free-space well-collimated beams at 461 nm and 689 nm wavelengths with customized beam profiles and emission angles needed for a Sr MOT. The device advanced photonics interfaces for atomic physics.
Photonic modal circulator using dynamic modulation with mirror symmetry
Authors: Wang Jiahui , Herrmann Jason , Witmer Jeremy , Safavi-Naeini Amir H. , Fan Shanhui
Published: August 2021

We show that a modal circulator can be achieved in a dynamically-modulated structure that preserves mirror symmetry. Such circulators can be implemented using only a single standing-wave modulator, which greatly simplifies the design of on-chip nonreciprocal devices based on dynamic modulations.
Implosion Fabrication as a Platform for Three-Dimensional Nanophotonics
Authors: Mills Brian , Salamin Yannick , Yang Gaojie , Oran Daniel , Sun Yi , Maayani Shai , Kooi Steven E. , Elawad Amel Amin Elfadil , Lopez Josue J. , Swain Corban , Beroz Justin , Sloan Jamison , Boyden Edward S. , Soljačić Marin
Published: August 2021

We investigate Implosion Fabrication, a technique which prints arbitrary 3D nanostructures, as a new platform for nanophotonics. We show that optical properties of printed materials are tunable by characterizing the reflectivity of printed silver.
Nanoscale Multiband Surface-enhanced Raman Spectroscopy by Multiresonant Nanolaminate Plasmonics
Authors: Nie Meitong , Zhao Yuming , Nam Wonil , Song Junyeob , Zhou Wei
Published: August 2021

By supporting multiple hybridized plasmonic modes within individual nanocavities, metal-insulator-metal nanolaminate plasmonic nanostructures on nanopillar arrays can enable nanoscale multiband SERS with large enhancement factors (> 106) over a wide visible to near-infrared spectral range.
Broadband Power Coupling and Splitting in Photonic Thouless Pump Systems
Authors: Sun Lu , Wang Hongwei , Zhang Yong , Su Yikai
Published: August 2021

By utilizing the topological transport property of Thouless pump, we experimentally demonstrate the broadband optical power coupling and splitting on the silicon photonic platform in the telecom band.
Unlocking coherent control of the extreme ultrafast plasmonic excitation
Authors: Bahar Eyal , Arieli Uri , Stern Maayan Vizner , Suchowski Haim
Published: August 2021

We experimentally coherent control the extreme ultrafast excitation in plasmonic nanostructures within their coherence lifetime. We predict and demonstrate a significant enhancement of the nonlinearity greater than the nonlinearity induced by a maximally compressed pulse.
Halide-Perovskite Metasurfaces Governed by the Kerker Effect
Authors: Baryshnikova Kseniia , Gets Dmitry , Liashenko Tatiana , Pushkarev Anatoly , Mukhin Ivan , Kivshar Yuri , Makarov Sergey
Published: August 2021

We design and demonstrate dramatic suppression of reflection from MAPbBr3 halide-perovskite metasurfaces. We employ the Kerker effect and engineer both electric and magnetic Mie resonances in each dielectric meta-atom to achieve a broadband performance.
Dynamic Crosstalk Monitoring of Real-time Transmission in Multi-core Fibers Based on Deep Learning
Authors: Zhang Maoqi , Li Kangjie , Gan Lin , Chen Yizhao , Zhao Can , Tang Ming
Published: August 2021

We propose and experimentally demonstrate a novel dynamic crosstalk monitoring in multi-core fibers based on deep learning, by using asynchronous amplitude histogram (AAH). The mean absolute error (MAE) of crosstalk monitoring is below 0.78 dB.
Independently Coupled and PZT Controllable Photonic Integrated Three-Resonator Photonic Molecule
Authors: Wang Jiawei , Liu Kaikai , Zhao Qiancheng , Isichenko Andrei , Rudy Ryan Q. , Blumenthal Daniel J.
Published: August 2021

We demonstrate an integrated three-resonator photonic molecule with independent buses and PZT controllable 5.11 million Q Si3N4 rings. Independent tuning is demonstrated with full control of resonances and splitting and verified with theory and simulation.
Optics for the Cloud: Challenges and Opportunities
Authors: Parmigiani Francesca , Haller Istvan , Gkantsidis Christos , Ballani Hitesh , Rowstron
Published: August 2021

This talk discusses some of the key challenges of designing future disruptive optical technologies for the Cloud, primarily in compute. A glimpse into some opportunities we see in the photonic space will also be covered.
Electrically controllable microlaser combs in graphene-fiber microresonators
Authors: Qin Chenye , Jia Kunpeng , Tan Teng , Guo Yanhong , Chang Bing , Zhang Hao , Xie Zhenda , Rao Yunjiang , Huang Shu-Wei , Yao Baicheng
Published: August 2021

Electrically controllable laser frequency combs are achieved in a 10 GHz graphene heterogeneous fiber microcavity. It demonstrates tunable mode-locking states with half-an-octave span and phase noise down to -120 dBc/Hz at 10 kHz.
Ultrafast High-Sensitivity Characterization of Refractive Index Transients Induced by Plasmas or Kerr Effect Using Cross-Polarized Common-Path Temporal Interferometry
Authors: Nie Zan , Marsh Kenneth A. , Nambu Noa , Huang Chen-Kang , Joshi Chan
Published: August 2021

A cross-polarized common-path temporal interferometer using balanced detection was developed for measuring refractive index transients due to plasmas or Kerr effect with a sensitivity of 0.5 mrad and a temporal resolution of 10 fs.
Bio-Inspired Photonics and Microwave Photonics for Dynamic and Smart RF Systems
Authors: Fok Mable , Liu Qidi
Published: August 2021

Bio-inspired and microwave photonics offer dynamic, natural, and effective solutions to tackle critical challenges in emerging RF systems. This paper discusses several small-scale bio- inspired and dynamic microwave photonic technologies to facilitate the advancement of RF systems.
Progress and Challenges of Plasmonics for Efficient and High-Speed Optical Communications
Authors: Hoessbacher Claudia , Baeuerle Benedikt , De Leo Eva , Medico Nino Del , Duran Hamit , Guesken Nicholas , Habegger Patrick , Heni Wolfgang , Meier Norbert
Published: August 2021

We present the ultra-high bandwidth plasmonics platform that enables efficient electro-optic modulation at micrometer scale. Applications in optical communications are discussed.
Microcavity lasers directly grown on silicon
Authors: Li Haochuan , Zhou Taojie , Zhang Zhan , Tang Mingchu , Chen Siming , Liu Huiyun , Zhang Zhaoyu
Published: August 2021

Monolithic integration of ultra-compact III-V light sources on silicon is promising for the Si-based on-chip optical interconnects. Here, we present quantum dots micro- cavity lasers monolithically grown on silicon with ultra-low energy consumption.
On spectral purity of a soliton microcomb as a function of pump detuning and mode temperature
Authors: Tetsumoto Tomohiro , Jiang Jie , Fermann Martin E. , Navickaite Gabriele , Geiselmann Michael , Rolland Antoine
Published: August 2021

We improve spectral purity of a repetition frequency of a 300 GHz soliton microcomb by 44 times down to frequency stability as low as 1.5×10
−
9 in empirically-driven experimental conditions that we describe in this work.
Complete SESAM Characterization via Equivalent Time Sampling Using a Free-Running Dual-Comb Laser
Authors: Nussbaum-Lapping Alexander , Pupeikis Justinas , Willenberg Benjamin , Phillips Christopher R. , Keller Ursula
Published: August 2021

Through pump-probe measurements with a free-running dual-comb laser, we demonstrate the validity range of a two time constant dynamical model for SESAM dynamics, and use it to show the fluence dependence of the time constants.
Polymer Optical Fibre Bend Sensor based on Eccentrical Bragg Gratings
Authors: Leffers Lennart , Locmelis Julia , Bremer Kort , Roth Bernhard , Overmeyer Ludger
Published: August 2021

We present a novel bend sensor based on eccentric fibre Bragg gratings in multimode graded-index polymer optical fibres. Dependent on number, position and depth of the gratings, 1D and 3D bend measurements are demonstrated.
Octave-spanning lithium niobate soliton microcombs
Authors: He Yang , Lopez-Rios Raymond , Yang Qifan , Ling Jingwei , Li Mingxiao , Vahala Kerry , Lin Qiang
Published: August 2021

We report lithium niobate soliton microcombs with spectral bandwidths exceeding one octave and spanning 125 THz to 268 THz.
High-efficiency and broadband electro-optic frequency combs using coupled lithium-niobate microresonators
Authors: Hu Yaowen , Yu Mengjie , Buscaino Brandon , Sinclair Neil , Zhu Di , Shams-Ansari Amirhassan , Shao Linbo , Zhang Mian , Kahn Joseph M. , Loncar Marko
Published: August 2021

We demonstrate an electro-optic frequency comb source, based on coupled lithium niobate microresonators, with a factor of 100 higher pump-to-comb conversion efficiency (30%) and 2.4 broader optical bandwidth (117 nm), as compared to the previous broadest electro-optic frequency comb.
Quantum Optomechanics with Millimeter Wave Photons
Authors: Hauer Bradley D. , Cicak Katarina , Lecocq Florent , Simmonds Raymond W. , Aumentado José , Teufel John D.
Published: August 2021

We present a new millimeter wave optomechanical cavity intended to increase the vacuum optomechanical coupling rate towards the regime of single-photon quantum optome- chanics.
Fluctuations and correlations of transmission eigenchannels within diffusive media
Authors: Bender Nicholas , Yamilov Alexey , Yılmaz Hasan , Cao Hui
Published: August 2021

We experimentally and numerically study the fluctuations and correlations of transmission eigenchannel profiles in diffusive media. We find that high-transmission profiles exhibit low realization-to-realization fluctuations and significant correlations exist between low-transmission profiles.
Foundry-Processed Optomechanical Mach-Zehnder Interferometers
Authors: Pruessner Marcel W. , Kozak Dmitry A. , Tyndall Nathan F. , Stievater Todd H. , Rabinovich William S.
Published: August 2021

We demonstrate foundry-processed optomechanical Mach-Zehnder interferometers using standard process development kit components and a post-process release. Measurements show clear optical phase shifting. Pump-probe experiments demonstrate all-optical excitation and readout of mechanical resonances.
Kerr-lens Mode-locked, Synchronously Pumped, Ultra-broadband Breathing Pulse Optical Parametric Oscillator
Authors: Fan Jintao , Zuber David , Mevert Robin , Lang Tino , Binhammer Thomas , Morgner Uwe
Published: August 2021

Profiting from a breathing pulse design, we demonstrate a Kerr-lens mode locked non-collinear optical parametric oscillator, which is capable of delivering stable ultrabroadband signal spanning from 628 nm to 890 nm at -10 dB level.
Deflector for resolution enhancement of head mounted displays and other visual systems
Authors: Ryu Jaeyeol , Muravev Nikolay , Piskunov Dmitry , Popov Mikhail , Lee Kyookeun , Kwak Kyusub , Choi Myongjo , Kim James D. K.
Published: August 2021

The resolution of a near eye display is improved by using a liquid crystal (LC) based deflector to tilt light at an angle equivalent to a sub-pixel. Potentially this technology can improve the resolution fourfold.
Solving Interdisciplinary Problems with Inverse-designed Photonics Integrated Circuits
Authors: Jia Hao , Yang Shanglin , Yang Lin
Published: August 2021

We present latest advances in using the photonics integrated devices and circuits for solving interdisciplinary problems. Especially, we focus on the efficient inverse-design optimization methodology, and ways to promote the circuits in multiple application scenes.
High power all-fiberized laser oscillator employing novel constant-cladding tapered-core Yb-doped fiber
Authors: Ye Yun , Lin Xianfeng , Xi Xiaoming , Yang Baolai , Shi Chen , Zhang Hanwei , Wang Xiaolin , Li Jinyan , Xu Xiaojun
Published: August 2021

In this work, we have proposed and fabricated a novel constant-cladding tapered-core (CCTC) Yb-doped fiber, which has a constant cladding diameter of ~600 μm and spindle-shaped core diameter with a ~20.8 μm at both ends and ~36.0 μm in the middle. Based on this CCTC fiber, an all-fiberized laser oscillator was constructed and investigated experimentally. The output power was scaled to 1514 W with an optical-to-optical efficiency of ~64%, and the measured beam quality (M2 factor) is ~1.6. The further power scaling is promising by optimizing the structure of the CCTC fiber.
Dual-pass Pre-chirp managed amplification with high gain and high average power
Authors: Zhang Yao , Wang Jingshang , Teng Hao , Fang Shaobo , Wang Junli , Chang Guoqing , Wei Zhiyi
Published: August 2021

We demonstrate the first dual-pass pre-chirp managed amplification in a rod-type Yb- fiber that amplifies 23-mW broadband pulses to 101.5-W with 36.5-dB gain. After compression, the system delivers 2-μJ, 67-fs pulses.
Dual-band 2-photon excitation dual-region imaging with subcellular resolution across 25mm2 field of view
Authors: Yu Che-Hang , Stirman Jeffery , Smith Spencer L.
Published: August 2021

We developed a dual-wavelength excitation, large field-of-view (25 mm2) two-photon microscope with temporal multiplexing and two completely independent scan engines coupled into the same objective for imaging in multiple areas with multiple wavelengths simultaneously.
Gain-switched semiconductor laser driven soliton microcombs
Authors: Weng Wenle , Kaszubowska-Anandarajah Aleksandra , He Jijun , Lakshmijayasimha Prajwal D. , Lucas Erwan , Liu Junqiu , Anandarajah Prince M. , Kippenberg Tobias J.
Published: August 2021

Using phase-engineered coherent laser pulses produced by gain-switched semiconductor lasers, we generate low-power-threshold soliton microcombs whose repetition frequencies are in the X-band and K-band microwave ranges.
Rydberg Atom-Based AC/DC Voltage Measurements
Authors: Prajapati Nikunjkumar , Robinson Amy K. , Norrgard Eric B. , Simons Matthew T. , Holloway Christopher L.
Published: August 2021

We determine DC and AC electric field strengths through measurements of Stark shifts in Rydberg electromagnetically-induced transparency. This demonstrates the potential for Rydberg atom-based calibrations of AC/DC voltage sources from 0-12 V.
Terahertz emissions by plasmas created from moderate to relativistic laser intensities
Authors: Bergé L.
Published: August 2021

While the energy of terahertz pulses produced by classical plasmas is limited to a few microjoules, it can reach the millijoule level at relativistic laser intensities. We review the main conversion mechanisms and current applications.
Single-Sideband Modulation Through Polarization Interband Transition in Thin-Film Lithium Niobate Waveguide
Authors: Zhu Di , Hu Yaowen , Desiatov Boris , Shao Linbo , Yu Mengjie , Lončar Marko
Published: August 2021

We demonstrate an electro-optic polarization modulator on thin-film lithium niobate. It realizes indirect interband transition between two polarization modes and enables non-reciprocal, single-sideband modulation.
Optical Gyrator and Microwave-to-Optical Converter using HBAR modes
Authors: Siddharth Anat , Blésin Terence , Tian Hao , Weng Wenle , Wang Rui Ning , Liu Junqiu , Bhave Sunil A. , Kippenberg Tobias J.
Published: August 2021

We demonstrate efficient modulation of optical resonators by partially releasing the substrate of an integrated MEMS-photonic stack. The increased interaction between the microwave and optical signals enables to realize gyrators as well as MW-optical converters.
Microring Modulators in a New Silicon Photonics-Optimized 45 nm Monolithic Electronics-Photonics SOI CMOS Platform
Authors: Al Qubaisi Kenaish , Khilo Anatol , Gevorgyan Hayk , Popović Miloš A.
Published: August 2021

We report on microring modulators in the new 45CLO photonics-optimized 45 nm electronic-photonic CMOS platform. Interdigitated disk and vertical-junction rib microring designs are demonstrated, with 20 GHz bandwidth at 25 Gbps data rate.
Loop Reflector Assisted Si-Ge Waveguide Avalanche Photodiodes
Authors: Yuan Yuan , Huang Zhihong , Zeng Xiaoge , Liang Di , Fiorentino Marco , Beausoleil Raymond G.
Published: August 2021

A Si-Ge waveguide avalanche photodiode with loop reflector has been demonstrated to enhance the responsivity without compromising the speed. It enables a responsivity of 1.12 A/W, a bandwidth of 25 GHz, a build-up time limited gain-bandwidth product of 296 GHz, and a highest gain-bandwidth product of 497 GHz.
Experimental Demonstration of a WDM-based Integrated Optical Decoder for Compact Optical Computing
Authors: Feng Chenghao , Gu Jiaqi , Zhu Hanqing , Pan David Z. , Chen Ray T.
Published: August 2021

We propose and experimentally demonstrate a 3-8 wavelength-division-multiplexing (WDM) based optical decoder using microring-based add-drop switches and filters. The proposed decoder has a smaller footprint and consumes lower power compared with previous designs.
Hybrid Chalcogenide-Silicon Subwavelength Grating Waveguides Microring Resonators
Authors: Jean Philippe , Douaud Alexandre , LaRochelle Sophie , Messaddeq Younès , Shi Wei
Published: August 2021

We present the fabrication and optical measurement of hybrid chalcogenide-silicon subwavelength grating waveguides microring resonators. The ring resonators exhibit nearly athermal behavior with dλ
r
/dT = –2.87 pm/K and intrinsic quality factor of Q
i
> 50000.
Graphdiyne-based saturable absorber for mode-locked erbium-doped fiber laser
Authors: Fan J. , Zhang M. , Wu Q. , Zheng Z. , Bao W. , Zhang H.
Published: August 2021

We demonstrate a self-starting, all-fiber erbium-doped laser mode-locked by graphdiyne-based saturable absorber, delivering 364 fs pulses with 9.18 nm spectral bandwidth. Our work highlights the potential of graphdiyne-based devices for future photonic technologies.
Permanent Optically-Induced Strain in hBN
Authors: Chen Cecilia Y. , Ginsberg Jared S. , Moore Samuel L. , Jadidi M. Mehdi , Li Baichang , Chae Sang Hoon , Watanabe Kenji , Taniguchi Takashi , Hone James , Basov Dmitri N. , Gaeta Alexander L.
Published: August 2021

We demonstrate the creation of permanent, localized strain structures in hBN with a phonon-resonant femtosecond laser at 7.3 µm. We spatially resolve the strain profile of the resulting micron-scale bubbles using Raman and AFM measurements.
Thermalization of Exciton-Polaritons in Strongly Coupled 2D Hybrid Perovskites
Authors: Deshmukh Prathmesh , Khatoniar Mandeep , Zhao Lianfeng , Rand Barry P. , Menon Vinod
Published: August 2021

We study thermalization of exciton-polaritons in 2D hybrid organic-inorganic perovskites strongly coupled to a planar microcavity. The integrated PL exhibits a bottleneck effect and the extracted lattice temperature shows cooling behavior of up to 35 meV.
PHz Electronic Device Design for Waveguide-Integrated Carrier-Envelope Phase Detection
Authors: Mor D. Cattozzo , Yang Y. , Singh N. , Ritzkowsky F. , Kärtner F. X. , Berggren K. K. , Keathley P. D.
Published: August 2021

We design and simulate electrically-connected plasmonic bow-tie nanoantennas integrated onto a Si3N4 waveguide for carrier-envelope-phase detection of few-cycle pulse trains. Our results demonstrate a promising route to waveguide-integrated petahertz electronics for CEP detection and stabilization.
Terahertz Pulse Shaping Using Diffractive Optical Networks
Authors: Veli Muhammed , Mengu Deniz , Yardimci Nezih T. , Luo Yi , Li Jingxi , Rivenson Yair , Jarrahi Mona , Ozcan Aydogan
Published: August 2021

We demonstrate diffractive optical networks that are trained with deep learning to engineer input terahertz pulses into desired temporal waveforms using passive diffractive surfaces that control the spectral phase and amplitude of the output pulse.
Flexible High-field Far-IR Source for Driving Nonlinear Phononics
Authors: Chang Wei-Zung , Zheng Jiaoyang , Flemens Noah , Heberle Dylan , Moses Jeffrey
Published: August 2021

We report a high-field sub-picosecond far-infrared (8–21 µm) tunable source with flexible control of bandwidth and pulse duration that can be used to study nonlinear phononic coupling effects arising from resonant excitation of infrared-active phonons.
Supercontinuum Generation in Optofluidic Microstructured Optical Fibers
Authors: Junaid Saher , Jörg Bierlich , Hartung Alexander , Chemnitz Mario , Schmidt Markus A.
Published: August 2021

Supercontinuum generation in microstructured optical fiber with as a core-material is presented. The sample provides a new dispersion landscape with the zero-dispersion-wavelength approaching telecommunication wavelengths allowing for intense nonlinear frequency broadening across near-infrared.
Intense Few-Cycle Pulse, Conical Pit Interaction Simulations Predicting Extreme Material States
Authors: Smith Joseph R. , Zhang Simin , Gruzdev Vitaly E. , Chowdhury Enam A.
Published: August 2021

We use fully three-dimensional particle-in-cell simulations to model intense few-cycle pulses interacting with nano-structured conical pits in fused silica and report on laser damage creation of high energy density conditions and excited electron dynamics.
Nano-Optic Broadband Power Splitter Design via Cycle-Consistent Adversarial Deep Learning
Authors: Tang Yingheng , Kojima Keisuke , Koike-Akino Toshiaki , Wang Ye , Jha Devesh K. , Parsons Kieran , Qi Minghao
Published: August 2021

A novel generative deep learning model with a cycle-consistent adversarial network is introduced for optimizing 550 nm broad bandwidth (1250 nm to 1800 nm) power splitters with arbitrary target splitting ratios.
Athermal WDM (de)multiplexer based on polysilicon cascaded Mach-Zehnder interferometers in bulk CMOS
Authors: Song Zhan-Wen , Tang Cheng-Tse , Huang Po-Hsiang , Hung Yung-Jr
Published: August 2021

We demonstrate an athermal WDM (de)multiplexer by realizing strip/subwavelength grating polysilicon waveguide based cascaded MZIs in bulk CMOS. Measured temperature sensitivity for all channels is around -20 pm/oC with a slope of -0.25 pm/oC/nm.
C and L band 1×12 AWG based on 3-μm SOI platform with 100 GHz channel spacing and low polarization sensitivity
Authors: Wang Yu , Srivathsa Bhat , Tessema Netsanet , Kraemer Rafael , Pan Bitao , Napoli Antonio , Delrosso Giovanni , Calabretta Nicola
Published: August 2021

C- and L-band polarization insensitive 1×12 AWG with 100GHz channel-spacing is fabricated on SOI. Results show <3.8dB loss, <-30dB crosstalk, <2.6dB polarization dependent loss, <0.1nm polarization dependent wavelength shift and <0.3dB BER penalty at 10Gbps.
Subcycle sampling of quantum fields with nonclassical temporal gates
Authors: Cusson Patrick , Virally Stephane , Seletskiy Denis V.
Published: August 2021

Time-domain analysis of quantum fields has been recently demonstrated through a nonlinear mixing with coherent-state probes. Here we consider nonclassical probes with engineered noise distributions to improve the detected fidelity of the quantum signals.
Nutzer, Sammler, Entscheidungsträger? Arten der Bürgerbeteiligung in Smart Cities
Authors: Haunschild Jasmin , Demuth Kilian , Geiß Henri-Jacques , Richter Christian , Reuter Christian
Published: August 2021

Digitalisierung ist ein präsenter Faktor in vielen Städten. So existieren bereits viele Smart-City-Initiativen, bei denen Städte versuchen, ihre Prozesse durch Erfassung und Verknüpfung von Daten, oft unter Zuhilfenahme von Datenplattformen, zu optimieren. In Anbetracht der damit einhergehenden großen Investitionen und Veränderungen wird Bürgerbeteiligung als zentraler Faktor für den Erfolg solcher Initiativen betrachtet. Bisher ist allerdings nicht klar, was typische Beteiligungsformate von Smart-City-Initiativen sind und welche Rolle(n) BürgerInnen dabei einnehmen. Dieser Beitrag leitet mittels einer Literaturanalyse zu Smart Cities ein Kategorienschema zu typischen Bürgerbeteiligungsarten ab. Die Analyse ergab, dass sich Einbindung von BürgerInnen in politische Entscheidungen und bei der Entwicklung technischer Artefakte maßgeblich auf e‑Government oder Participatory Design bezieht. Im Hinblick auf die Beteiligungsarten zeigt sich, dass Makrofabriken, Living Labs und Open-Data-Plattformen häufige Ansätze sind, um BürgerInnen als Co-Creators einzubinden. Zudem werden BürgerInnen mit Citizen Sensing zur Erfassung von Daten oder Missständen einbezogen. Dabei zeigen sich sowohl aktivere, als auch eher passive Beteiligungsarten. Die Analyse zeigt, dass die Einbindung von BürgerInnen häufig entweder auf eine Beteiligung an politischen Entscheidungen oder an der Entwicklung technischer Artefakte abzielt. Auch wenn keine klare Abgrenzung möglich ist, sind diese Ansätze dann eher durch e‑Government oder Participatory Design inspiriert.
Four methods of brain pattern analyses of fMRI signals associated with wrist extension versus wrist flexion studied for potential use in future motor learning BCI
Authors: Ravindran Aniruddh , Rieke Jake D. , Zapata Jose Daniel Alcantara , White Keith D. , Matarasso Avi , Yusufali M. Minhal , Rana Mohit , Gunduz Aysegul , Modarres Mo , Sitaram Ranganatha , Daly Janis J.
Published: August 2021

Objective

In stroke survivors, a treatment-resistant problem is inability to volitionally differentiate upper limb wrist extension versus flexion. When one intends to extend the wrist, the opposite occurs, wrist flexion, rendering the limb non-functional. Conventional therapeutic approaches have had limited success in achieving functional recovery of patients with chronic and severe upper extremity impairments. Functional magnetic resonance imaging (fMRI) neurofeedback is an emerging strategy that has shown potential for stroke rehabilitation. There is a lack of information regarding unique blood-oxygenation-level dependent (BOLD) cortical activations uniquely controlling execution of wrist extension versus uniquely controlling wrist flexion. Therefore, a first step in providing accurate neural feedback and training to the stroke survivor is to determine the feasibility of classifying (or differentiating) brain activity uniquely associated with wrist extension from that of wrist flexion, first in healthy adults.

Approach

We studied brain signal of 10 healthy adults, who performed wrist extension and wrist flexion during fMRI data acquisition. We selected four types of analyses to study the feasibility of differentiating brain signal driving wrist extension versus wrist flexion, as follows: 1) general linear model (GLM) analysis; 2) support vector machine (SVM) classification; 3) ‘Winner Take All’; and 4) Relative Dominance.

Results

With these four methods and our data, we found that few voxels were uniquely active during either wrist extension or wrist flexion. SVM resulted in only minimal classification accuracies. There was no significant difference in activation magnitude between wrist extension versus flexion; however, clusters of voxels showed extension signal > flexion signal and other clusters vice versa. Spatial patterns of activation differed among subjects.

Significance

We encountered a number of obstacles to obtaining clear group results in healthy adults. These obstacles included the following: high variability across healthy adults in all measures studied; close proximity of uniquely active voxels to voxels that were common to both the extension and flexion movements; in general, higher magnitude of signal for the voxels common to both movements versus the magnitude of any given uniquely active voxel for one type of movement. Our results indicate that greater precision in imaging will be required to develop a truly effective method for differentiating wrist extension versus wrist flexion from fMRI data.
Collection, genotyping and virus elimination of cassava landraces from Tanzania and documentation of farmer knowledge
Authors: Ferguson M. E. , Tumwegamire S. , Chidzanga C. , Shah T. , Mtunda K. , Kulembeka H. , Kimata B. , Tollano S. , Stephen M. , Mpayo E. , Mohamedi S. , Kasele S. , Palangyo E. , Armachius J. , Hamad Ali A. , Sichalwe K. , Matondo D. , Masisila F. , Matumbo Z. , Kidunda B. , Arati A. C. , Muiruri R. , Munguti F. , Abass A. , Abberton M. , Mkamilo G.
Published: August 2021

Cassava (Manihot esculenta Crantz.) has been a vital staple and food security crop in Tanzania for several centuries, and it is likely that its resilience will play a key role in mitigating livelihood insecurities arising from climate change. The sector is dominated by smallholder farmers growing traditional landrace varieties. A recent surge in virus diseases and awareness in the commercial potential of cassava has prompted a drive to disseminate improved varieties in the country. These factors however also threaten the existence of landraces and associated farmer knowledge. It is important that the landraces are conserved and utilized as the adaptive gene complexes they harbor can drive breeding for improved varieties that meet agro-ecological adaptation as well as farmer and consumer needs, thereby improving adoption rates. Here we report on cassava germplasm collection missions and documentation of farmer knowledge in seven zones of Tanzania. A total of 277 unique landraces are identified through high-density genotyping. The large number of landraces is attributable to a mixed clonal/sexual reproductive system in which the soil seed bank and incorporation of seedlings plays an important role. A striking divergence in genetic relationships between the coastal regions and western regions is evident and explained by (i) independent introductions of cassava into the country, (ii) adaptation to prevailing agro-ecological conditions and (iii) farmer selections according to the intended use or market demands. The main uses of cassava with different product profiles are evident, including fresh consumption, flour production, dual purpose incorporating both these uses and longer-term food security. Each of these products have different trait requirements. Individual landraces were not widely distributed across the country with limited farmer-to-farmer diffusion with implications for seed systems.
Application of biological and fisheries attributes to assess the vulnerability and resilience of tropical marine fish species
Authors: Mohamed Kolliyil S. , Sathianandan Thayyil Valappil , Vivekanandan Elayaperumal , Kuriakose Somy , Ganga U. , Pillai Saraswathy Lakshmi , Nair Rekha J.
Published: August 2021

Taking advantage of published data on life-history traits and short-term information on fishery parameters from 3132 records for 644 fish stocks along the coast of India, we calculated resilience (R) and vulnerability (V). Further, we developed an Index of Resilience and Vulnerability (IRV) for 133 species of tropical finfishes, crustaceans, and molluscs. Using 7 resilience and 6 vulnerability attributes, two-dimensional scatter plots of the resilience and vulnerability scores were generated and the Euclidean distance and angle from the origin to each point were calculated to determine IRV and the effect of fishing on fish species. By ranking the species, the top 10 highly resilient, highly vulnerable, and high-risk species (low IRV) were identified. While small-sized species with fast growth rate and low trophic level were among the highly resilient species, large predatory species such as sharks and barracudas were among the highly vulnerable and high-risk species. More than 100 of the 133 species were resilient-yet-vulnerable, and most crustaceans showed high resilience. Differences in IRV scores among species within the same family were discernible, indicating the differences in the biological characteristics and response to fishing. Sensitivity analysis indicated that an abridged IRV with 6 attributes works similar to 13 attributes and can be used in data-deficient situations. Comparison of R and V of IRV with other assessments showed different results because of divergences in the objectives, number and types of attributes, and thresholds used. These assessments do not convey the same information and therefore great care must be taken for reproducing these frameworks to other fisheries. The results of IRV analysis can be useful for stock assessments and in developing effective management measures in combination with other complementary information.
Thyroid hormone deficiency during zebrafish development impairs central nervous system myelination
Authors: Farías-Serratos Brenda Minerva , Lazcano Iván , Villalobos Patricia , Darras Veerle M. , Orozco Aurea
Published: August 2021

Thyroid hormones are messengers that bind to specific nuclear receptors and regulate a wide range of physiological processes in the early stages of vertebrate embryonic development, including neurodevelopment and myelogenesis. We here tested the effects of reduced T3 availability upon the myelination process by treating zebrafish embryos with low concentrations of iopanoic acid (IOP) to block T4 to T3 conversion. Black Gold II staining showed that T3 deficiency reduced the myelin density in the forebrain, midbrain, hindbrain and the spinal cord at 3 and 7 dpf. These observations were confirmed in 3 dpfmbp:egfptransgenic zebrafish, showing that the administration of IOP reduced the fluorescent signal in the brain. T3 rescue treatment restored brain myelination and reversed the changes in myelin-related gene expression induced by IOP exposure. NG2 immunostaining revealed that T3 deficiency reduced the amount of oligodendrocyte precursor cells in 3 dpf IOP-treated larvae. Altogether, the present results show that inhibition of T4 to T3 conversion results in hypomyelination, suggesting that THs are part of the key signaling molecules that control the timing of oligodendrocyte differentiation and myelin synthesis from very early stages of brain development.
Delineating reclamation zones for site-specific reclamation of saline-sodic soils in Dushak, Turkmenistan
Authors: Günal Elif
Published: August 2021

Soil salinization is the widespread problem seriously affecting the agricultural sustainability and causing income losses in arid regions. The major objective of the study was to quantify and map the spatial variability of soil salinity and sodicity. Determining salinity and sodicity variability in different soil layers was the second objective. Finally, proposing an approach for delineating different salinity and sodicity zones was the third objective. The study was carried out in 871.1 ha farmland in Southeast of Dushak town of Ahal Province, Turkmenistan. Soil properties, including electrical conductivity (EC), soil reaction (pH), sodium adsorption ratio (SAR), calcium carbonate and particle size distribution (clay, silt and sand fractions) in 0–30, 30–60, 60–90 and 90–120 cm soil layers were recorded. The EC values in different soil layers indicated serious soil salinization problem in the study area. The mean EC values in 0–90 cm depth were high (8 dS m-1), classifying the soils as moderate to strongly saline. Spatial dependence calculated by the nugget to sill ratio indicated a strong spatial autocorrelation. The elevation was the primary factor affecting spatial variation of soil salinity in the study area. The reclamation of the field can be planned based on three distinct areas, i.e., high (≥12 dS m-1), moderate (12–8 dS m-1) and low (<8 dS m-1) EC values. The spatial trend analyses of SAR values revealed similar patterns for EC and pH; both of which gradually decreased from north to the south-west. The amount of water needed to leach down the salts from 60 cm of soil profile is between 56.4–150.0 ton ha-1and the average leaching water was 89.8 tons ha-1. The application of leaching water based on the amount of average leaching water will result in higher or lower leaching water application to most locations and the efficiency of the reclamation efforts will be low. Similar results were recorded for sulfur, sulfuric acid and gypsum requirements to remediate sodicity. The results concluded that the best management strategy in planning land development and reclamation schemes for saline and sodic soils require accurate information about the spatial distribution of salinity and sodicity across the target area.
Preoperative Fear, Operative Gear, and Postoperative Care, in Tracheostomy during Covid Times – Our Experience at a Tertiary Care Hospital
Authors: Datta Ginni , Narang Sumit , Gupta Manish , Arora Soniya
Published: August 2021

BACKGROUND The SARS-CoV-2 is known to be highly contagious from respiratory tract droplets and aerosol exposure. ENT surgeons deal with the upper airway and are exposed to aerosol generating procedures on a daily basis. Aerosol generating procedure such as tracheostomy is necessary in patients with head and neck cancers having airway obstruction. METHODS We share our experience of 38 cases where we had to perform tracheostomy during these Covid times under various circumstances in a tertiary care centre with a dedicated Covid Isolation centre for 5 districts with 210 beds reserved for Covid patients. RESULTS All 38 tracheostomies were performed successfully following the guidelines formulated by our team, with proper precautions not a single team member got infected with Covid-19. No test is 100 % sensitive, so all precautions must be taken while dealing with every patient and PPEs should be used in all tracheostomies. CONCLUSIONS No test is 100 % sensitive, so all precautions must be taken while dealing with every patient and PPEs should be used in all tracheostomies. Our policy of anticipating tracheostomy in patients with impending stridor helped us reduce the risk of having to perform emergency tracheostomies with Covid status unknown. KEY WORDS Aerosol, COVID-19, PPE - Kit, SARS-CoV-2, Stridor, Tracheostomy
Effectiveness of Ultrasonography Guided Femoral Nerve Block for Patient Positioning during Central Neuraxial Block in Elderly Patients for Fracture of Femur - A Prospective, Randomized Control Trial
Authors: Barman Ratindra Kumar , Basumatary Karamchand , Hazarika Ananta
Published: August 2021

BACKGROUND Central neuraxial blocks, mainly spinal anaesthesia is the preferred anaesthesia over general anaesthesia in fracture of femur surgeries in elderly patients because of various side effects associated with general anaesthesia. However, the majority of the patients during positioning for spinal anaesthesia are associated with severe pain for which positioning becomes difficult. We wanted to assess the effectiveness of ultrasound (USG) guided femoral nerve block (FNB) to reduce pain during the positioning for spinal anaesthesia in fracture femur patients. METHODS It was a randomized control trial conducted on 80 elderly ASA I, II and III patients (45 - 70 years) posted for various femur surgeries under spinal anaesthesia having visual analogue scale (VAS) ≥ 4 during positioning. Patients in group FNB (N = 40) received USG guided femoral nerve block with 0.2 % ropivacaine and in control group (N = 40) didn’t receive any interventions preoperatively. All patients received injection fentanyl during positioning if VAS ≥ 4. Parameters recorded included VAS at baseline, 15 mins and during positioning, anaesthesiologist’s satisfaction (yes or no), total fentanyl consumption and patient’s satisfaction (Likert scale). RESULTS Demographic variables were comparable to each group. VAS in FNB at 15 mins and during positioning was 2.3 ± 1.042 and 3.025 ± 0.831 in comparison to 6.125 ± 0.607 and 7.2 ± 0.822 in control group respectively. Only 5 patients required injection fentanyl and total consumption was 142 ± 3.21 µg in FNB group while all patients in control group required injection fentanyl and total consumption was 1162 ± 4.43 µg. Anaesthesiologists and patients satisfaction were much higher in FNB group. CONCLUSIONS USG - guided FNB is very effective in controlling pain during positioning for spinal anaesthesia in fracture femur patients. KEY WORDS Ultrasound, Femoral Nerve Block, Spinal Anaesthesia, Ropivacaine, Fracture Femur
Evaluating the Efficacy of Two Decalcifying Agents on Hard and Soft Tissues of Human Permanent Teeth
Authors: Ali Sheeba , Bansal Puja , Bhargava Deepak , Choudhary Ashish , Hasti Anurag , Chandravarkar Vidyadevi , Mishra Mithilesh , Singh Shafali
Published: August 2021

BACKGROUND Human teeth and bones consist of hard and soft tissues. Preparing calcified tissues for histological analysis by decalcification is a time-consuming procedure, and the quality of the sections thus obtained is dependent on the speed with which decalcification occurs, as well as the chemistry of the decalcification agent. The present study was intended to identify the method that combines the highest quality of stained sections with a short period of time. METHODS 50 extracted premolars were subjected to decalcification using 10 % Formic acid and 5 % Trichloroacetic acid (TCA). The efficacy of decalcifying agents was evaluated by recording the time taken by particular acid to decalcify the tooth completely. The preservation of morphological characteristics was assessed on the basis of ease of sectioning, uniformity of staining, damage to odontoblast layer, retraction of pulp and fraying of dentinal tubules. RESULTS Comparatively decalcification was faster with 5 % TCA than 10 % Formic acid. Whereas, 10 % formic acid was more considerate on soft tissues than 5 % TCA. All the results were statistically significant. CONCLUSIONS Samples decalcified with 10 % formic acid gave fairly good results, so it can be used in cases of diagnostic urgencies. KEY WORDS Teeth, Decalcification, Acids, Histopathology
Study of Retinal Nerve Fibre Layer Thickness in Diabetics - with and without Diabetic Retinopathy
Authors: Shinde Pranaykumar
Published: August 2021

BACKGROUND Diabetes mellitus is a heterogeneous group of diseases, characterized by a state of chronic hyperglycemia, resulting from varied aetiologies. Diabetic retinopathy (DR) is the most common ocular complication of diabetes with 5 % of diabetics, progressing to severe visual loss of 5/200 or less. 3 Very few studies have been conducted on optical coherence tomography (OCT) changes in diabetic retinopathy in Indian scenario. We wanted to evaluate the association of retinal nerve fibre layer (RNFL) thickness with diabetic retinopathy and assess the possibility of RNFL thickness changes being a precursor to diabetic retinal changes. METHODS A cross sectional study was conducted at the Department of Ophthalmology, Acharya Vinobha Bhave Rural Hospital. A total of 120 patients were enrolled for the study and divided into four groups of equal population as controls / non-diabetics (NDM), diabetics without retinopathy (NDR), diabetics with non-proliferative diabetic retinopathy (NPDR) and diabetics with proliferative retinopathy (PDR). Patients were evaluated for visual acuity, RNFL thickness, intraocular pressure(IOP), cup disc ratio in each case and data was statistically analysed. RESULTS Mean temporal RNFL thickness in PDR group was 73.72 ± 15.22 and was statistically significant (P = 0.0001) than temporal RNFL thickness in controls (60.41 ± 7.56), NDR (61.06 ± 6.51) and NPDR (59.01 ± 5.51). Mean cup-disc disc ratio was 0.26 ± 0.08 in controls, was 0.28 ± 0.11 in NDR group, 0.32 ± 0.08 in NPDR group and 0.36 ± 0.11 in PDR group and was statistically significant (P = 0.026). However no statistically significant difference was seen in global average RNFL thickness across groups though it was more in NPDR and PDR when compared to NDM group, and was least in NDR group. CONCLUSIONS There was statistically significant increase in temporal RNFL thickness in diabetic group which worsens with the disease. Hence temporal RNFL thickness may be estimated in diabetic patients to predict transformation to diabetic retinopathy and intervene at an early stage. KEY WORDS Diabetes Mellitus, Retinal Nerve Fibre Layer, Proliferative Diabetic Retinopathy, Non Proliferative Diabetic Retinopathy