On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

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The Observation of Gravitational Waves from a Binary Black Hole Merger

Our understanding of the cellular implementation of systems-level neural processes like action, thought and emotion has been limited by the availability of tools to interrogate specific classes of neural cells within intact, living brain tissue. Here we identify and develop an archaeal light-driven chloride pump (NpHR) from Natronomonas pharaonis for temporally precise optical inhibition of neural activity. NpHR allows either knockout of single action potentials, or sustained blockade of spiking. NpHR is compatible with ChR2, the previous optical excitation technology we have described, in that the two opposing probes operate at similar light powers but with well-separated action spectra. NpHR, like ChR2, functions in mammals without exogenous cofactors, and the two probes can be integrated with calcium imaging in mammalian brain tissue for bidirectional optical modulation and readout of neural activity. Likewise, NpHR and ChR2 can be targeted together to Caenorhabditis elegans muscle and cholinergic motor neurons to control locomotion bidirectionally. NpHR and ChR2 form a complete system for multimodal, high-speed, genetically targeted, all-optical interrogation of living neural circuits.

Multimodal fast optical interrogation of neural circuitry

* The only book describing applications of nonlinear fiber optics * Two new chapters on the latest developments: highly nonlinear fibers and quantum applications* Coverage of biomedical applications* Problems provided at the end of each chapterThe development of new highly nonlinear fibers - referred to as microstructured fibers, holey fibers and photonic crystal fibers - is the next generation technology for all-optical signal processing and biomedical applications. This new edition has been thoroughly updated to incorporate these key technology developments.The book presents sound coverage of the fundamentals of lightwave technology, along with material on pulse compression techniques and rare-earth-doped fiber amplifiers and lasers. The extensively revised chapters include information on fiber-optic communication systems and the ultrafast signal processing techniques that make use of nonlinear phenomena in optical fibers.New material focuses on the applications of highly nonlinear fibers in areas ranging from wavelength laser tuning and nonlinear spectroscopy to biomedical imaging and frequency metrology. Technologies such as quantum cryptography, quantum computing, and quantum communications are also covered in a new chapter.This book will be an ideal reference for: RD scientists involved with research on fiber amplifiers and lasers; graduate students and researchers working in the fields of optical communications and quantum information. * The only book on how to develop nonlinear fiber optic applications* Two new chapters on the latest developments; Highly Nonlinear Fibers and Quantum Applications* Coverage of biomedical applications

Applications of nonlinear fiber optics

Under strong laser radiation, a Dirac material, the topological insulator (TI) Bi2Te3, exhibits an optical transmittance increase as a result of saturable absorption. Based on an open-aperture Z-scan measurement at 1550 nm, we clearly show that the TI, Bi2Te3 under our investigation, is indeed a very-high-modulation-depth (up to 95%) saturable absorber. Furthermore, a TI based saturable absorber device was fabricated and used as a passive mode locker for ultrafast pulse formation at the telecommunication band. This contribution unambiguously shows that apart from its fantastic electronic property, a TI (Bi2Te3) may also possess attractive optoelectronic property for ultrafast photonics.

Ultra-short pulse generation by a topological insulator based saturable absorber

The emergence of novel two-dimensional (2D) monoelemental materials (Xenes) has shown remarkable potential for their applications in different fields of technology, as well as addressing new discoveries in fundamental science. Xenes (e.g., borophene, silicene, germanene, stanene, phosphorene, arsenene, antimonene, bismuthene, and tellurene) are of particular interest because they are the most chemically tractable materials for synthetic exploration. Owing to their excellent physical, chemical, electronic and optical properties, Xenes have been regarded as promising agents for biosensors, bioimaging, therapeutic delivery, and theranostics, as well as in several other new bio-applications. In this tutorial review, we summarize their general properties including the classification of Xenes according to their bulk properties. The synthetic and modification methods of Xenes are also presented. Furthermore, the representative Xene nanoplatforms for various biomedical applications are highlighted. Finally, research progress, challenges, and perspectives for the future development of Xenes in biomedicines are discussed.

Emerging two-dimensional monoelemental materials (Xenes) for biomedical applications

Designed a zero velocity detection algorithm based on adaptive threshold in order to accurately detect the zero velocity moment, and through the Kalman zero velocity correction algorithm timely correct the error of inertial navigation system(INS). Because at zero velocity correction time position and heading information is observed, by unscented Kalman filter (UKF) INS and GPS are integrated navigation and compared with extended Kalman filter (EKF). Through the experiment under the condition of strong nonlinear UKF has better filtering performance than EKF, and also better than the EKF on rapidity. Using Kalman zero velocity correction and UKF building federal filtering model can effectively inhibit the INS position drift problem. At the same time, in straight line phase, the use of GPS location information correct course angle. When GPS signal loss within a certain time' the integrated navigation system can get the right course angle. Thus, the positioning accuracy of the integrated navigation system is obviously improved.

http://ieeexplore.ieee.org/iel7/7510582/7530943/07531934.pdf

A federated filtering personal navigation algorithm based on MEMS-INS/GPS integrated

Principal component analysis (PCA) is a common fault detection method. But it is difficult to get high accuracy· if it is applied to complex nonlinear system. Faced with complex system such as chiller· this paper proposes using kernel principal component analysis (KPCA) for fault detection. But· the selection of kernel parameters is a problem in the implement of KPCA algorithm. Genetic algorithm (GA) is used to determine the kernel parameter through minimizing false alarm rate and maximizing detection rate. This method is verified by ASHRAE 1043-RP data. The results show that it is better than PCA. And it can improve the accuracy of fault detection.

Fault detection of chiller based on improved KPCA

The invention provides a polarization-maintaining hollow fiber, comprising a cladding area and a fiber core area determined by the cladding area. The cladding area comprises a plurality of slave cladding areas. The slave cladding areas at any two positions which are symmetrical relative to the fiber core area have the same thickness. As for the orthogonal direction of the line of any two positions, the slave cladding areas at two positions which are symmetrical relative to the fiber core area along the orthogonal direction have different thickness as that of the slave cladding areas at any twopositions. The refractive index of the cladding area is greater than that of the fiber core area. The invention is advantageous in that the hollow fiber having the function of polarization maintaining can be realized through the cladding areas having different thicknesses along the orthogonal direction, and the polarization-maintaining hollow fiber can be widely applied in high-quality fiber gyroscopes, precise interference sensing, quantum calculating, atomic spectrums, and polarization-maintaining optical amplifiers.

Polarization-maintaining hollow fiber

We report on the generation of bound states of pulses in a SESAM mode-locked Cr:ZnSe laser around 2415 nm. A thulium-doped double-clad fiber laser at 1908 nm was used as the pump source. Bound states with various pulse separations at different dispersion regimes were obtained. Especially, in the anomalous dispersion regime, vibrating bound state of solitons exhibiting an evolving phase was obtained.

Generation of bound states of pulses in a SESAM mode-locked Cr:ZnSe laser

The invention provides a blue-light and ultraviolet-light enhancing super-continuum spectrum laser device of a full-fiber structure, and belongs to the fields of the laser technology and the non-linear optics. The blue-light and ultraviolet-light enhancing super-continuum spectrum laser device specifically comprises a pumping source, a fiber amplifier and a tapered quartz photonic crystal fiber, wherein the pumping source, the fiber amplifier and the tapered quartz photonic crystal fiber are sequentially connected. The pumping source is a non-linear polarization rotary mode-locked laser device body of the full-fiber structure. The fiber amplifier comprises a single-mode fiber amplifier body and double-clad fiber amplifier bodies. Meanwhile, a quartz photonic crystal fiber is tapered through a fiber drawing tower or a fiber tapering machine to increase blue light contents and ultraviolet light contents in a super-continuum spectrum. The super-continuum spectrum generated through the blue-light and ultraviolet-light enhancing super-continuum spectrum laser device has the advantages of being high in blue light content and ultraviolet light content, good in spectrum flatness, large in spectrum bandwidth and high in coupling efficiency and conversion efficiency.

Pu Wang

Papers

A federated filtering personal navigation algorithm based on MEMS-INS/GPS integrated

Fault detection of chiller based on improved KPCA

Polarization-maintaining hollow fiber

Generation of bound states of pulses in a SESAM mode-locked Cr:ZnSe laser

Blue-light and ultraviolet-light enhancing super-continuum spectrum laser device of full-fiber structure